1 00:00:04,280 --> 00:00:01,189 okay now that I've got your attention 2 00:00:06,499 --> 00:00:04,290 because they're changing pictures I'd 3 00:00:10,430 --> 00:00:06,509 like to welcome everybody to our July 4 00:00:12,110 --> 00:00:10,440 open night your guests usual host Frank 5 00:00:14,240 --> 00:00:12,120 summers is on travel 6 00:00:16,640 --> 00:00:14,250 that means you'll get home early enough 7 00:00:18,800 --> 00:00:16,650 to let the cat out tonight I'm just 8 00:00:21,769 --> 00:00:18,810 teasing and there won't be a quiz after 9 00:00:23,090 --> 00:00:21,779 the talk my name is Ray Vallarta I'm the 10 00:00:25,580 --> 00:00:23,100 news director here at the Space 11 00:00:28,220 --> 00:00:25,590 Telescope Institute we've got a 12 00:00:30,710 --> 00:00:28,230 fascinating talk tonight dealing with 13 00:00:34,850 --> 00:00:30,720 our cosmic origins the origin of the 14 00:00:37,069 --> 00:00:34,860 solar system and the planets the Frank 15 00:00:38,780 --> 00:00:37,079 usually gives you the big Hubble news 16 00:00:41,540 --> 00:00:38,790 rundown I have the Reader's Digest 17 00:00:43,729 --> 00:00:41,550 version and I'm going to show you one 18 00:00:45,920 --> 00:00:43,739 item and I wanted to show you this 19 00:00:50,389 --> 00:00:45,930 tonight because it dovetails with what 20 00:00:53,029 --> 00:00:50,399 our guests will be talking about but the 21 00:00:55,459 --> 00:00:53,039 the the news just came out today so you 22 00:00:56,900 --> 00:00:55,469 may not have heard about it so I'm not 23 00:01:04,429 --> 00:00:56,910 going to give you a quiz but who can 24 00:01:12,550 --> 00:01:04,439 tell me what spacecraft is that now 25 00:01:15,230 --> 00:01:12,560 you're off by 40 years nobody okay 26 00:01:19,969 --> 00:01:15,240 no but you're getting warmer 27 00:01:21,649 --> 00:01:19,979 or should I say colder come on you guys 28 00:01:24,160 --> 00:01:21,659 paid a billion dollars for this 29 00:01:26,810 --> 00:01:24,170 spacecraft 30 00:01:31,069 --> 00:01:26,820 oh you're getting colder you keep track 31 00:01:33,590 --> 00:01:31,079 for any money goes yes not Voyager 32 00:01:34,880 --> 00:01:33,600 that's way the hell out and it's I don't 33 00:01:38,990 --> 00:01:34,890 think it's beyond the edge of the solar 34 00:01:42,050 --> 00:01:39,000 system that's my person right here okay 35 00:01:46,160 --> 00:01:42,060 I will because times going this is the 36 00:01:47,660 --> 00:01:46,170 New Horizons craft headed for Pluto it 37 00:01:51,050 --> 00:01:47,670 is controlled here at the Applied 38 00:01:54,980 --> 00:01:51,060 Physics lab down outside of Columbia and 39 00:01:56,870 --> 00:01:54,990 this craft was launched 10 years ago it 40 00:02:00,020 --> 00:01:56,880 is the fastest man-made object ever 41 00:02:03,139 --> 00:02:00,030 built and this is a trajectory as of 42 00:02:05,120 --> 00:02:03,149 today it is a marathon runner it has 43 00:02:08,210 --> 00:02:05,130 sprinted across the orbits of all the 44 00:02:10,419 --> 00:02:08,220 major planets it is a year from flying 45 00:02:12,819 --> 00:02:10,429 by the planet Pluto 46 00:02:17,619 --> 00:02:12,829 and with Frank not here I can say planet 47 00:02:20,710 --> 00:02:17,629 tweet are actually was Pluto is a dwarf 48 00:02:23,830 --> 00:02:20,720 binary planet an interesting idea which 49 00:02:25,210 --> 00:02:23,840 gets lost in all the silly fight over 50 00:02:27,699 --> 00:02:25,220 the semantics of what to call it 51 00:02:31,869 --> 00:02:27,709 whatever Pluto is it's very interesting 52 00:02:33,970 --> 00:02:31,879 it will reach Pluto in July but the 53 00:02:37,030 --> 00:02:33,980 people running new horizons would like 54 00:02:40,809 --> 00:02:37,040 to go farther they'd like to boldly go 55 00:02:44,050 --> 00:02:40,819 even deeper into the solar system so the 56 00:02:47,140 --> 00:02:44,060 outer rim of the solar system is a vast 57 00:02:49,890 --> 00:02:47,150 undiscovered country stretching from 3 58 00:02:52,809 --> 00:02:49,900 billion to 5 billion miles from the Sun 59 00:02:55,179 --> 00:02:52,819 it contains primordial debris going back 60 00:02:58,089 --> 00:02:55,189 to the birth of our solar system 4.6 61 00:03:00,550 --> 00:02:58,099 billion years ago we've never been there 62 00:03:04,720 --> 00:03:00,560 and we only know it about objects out 63 00:03:06,640 --> 00:03:04,730 there since the 1990s the folks on the 64 00:03:09,129 --> 00:03:06,650 new Horizons probe after they fly by 65 00:03:11,940 --> 00:03:09,139 Pluto wanted to visit a Kuiper belt 66 00:03:14,619 --> 00:03:11,950 object these are objects that range in a 67 00:03:16,720 --> 00:03:14,629 variety of sizes typically the one that 68 00:03:19,420 --> 00:03:16,730 the one they want to fly by is about the 69 00:03:22,240 --> 00:03:19,430 size of Manhattan Island but we have to 70 00:03:24,129 --> 00:03:22,250 find it and only Hubble only Hubble not 71 00:03:26,259 --> 00:03:24,139 any ground-based telescope has the 72 00:03:29,020 --> 00:03:26,269 ability to look for targets for the new 73 00:03:31,509 --> 00:03:29,030 Horizons probe so just released today 74 00:03:34,839 --> 00:03:31,519 our pictures of two Kuiper belt objects 75 00:03:36,399 --> 00:03:34,849 these are extraordinarily faint they're 76 00:03:38,649 --> 00:03:36,409 about as faint as the glow of a 77 00:03:41,289 --> 00:03:38,659 flashlight on the moon if you could see 78 00:03:43,539 --> 00:03:41,299 it from Earth now how do we know that 79 00:03:49,370 --> 00:03:43,549 these are Kuiper belt objects because 80 00:03:56,130 --> 00:03:53,040 god these are these two objects are four 81 00:03:57,390 --> 00:03:56,140 billion miles from the Sun well how do 82 00:03:59,400 --> 00:03:57,400 we know they belong in the Kuiper belt 83 00:04:01,680 --> 00:03:59,410 because they're moving against the 84 00:04:03,570 --> 00:04:01,690 background of stars that background is 85 00:04:05,490 --> 00:04:03,580 in the summer constellation Sagittarius 86 00:04:08,760 --> 00:04:05,500 so finding these was like playing a game 87 00:04:11,010 --> 00:04:08,770 of Where's Waldo it was it was a needle 88 00:04:13,050 --> 00:04:11,020 in haystack search we announced today 89 00:04:15,510 --> 00:04:13,060 that we found two of them this means 90 00:04:17,400 --> 00:04:15,520 that more than 140 Hubble orbits will be 91 00:04:19,199 --> 00:04:17,410 dedicated to looking for more Kuiper 92 00:04:23,460 --> 00:04:19,209 belt objects which would be suitable 93 00:04:26,700 --> 00:04:23,470 targets for new horizons so but probably 94 00:04:29,670 --> 00:04:26,710 by the year 2020 if we find if that team 95 00:04:31,590 --> 00:04:29,680 finds a suitable Kuiper belt object it 96 00:04:34,260 --> 00:04:31,600 will fly by that object and what this 97 00:04:35,850 --> 00:04:34,270 will be this will complete mankind's 98 00:04:38,450 --> 00:04:35,860 initial reconnaissance of the solar 99 00:04:40,800 --> 00:04:38,460 system going back to the early 60s 100 00:04:43,020 --> 00:04:40,810 because these Kuiper belt objects are 101 00:04:45,450 --> 00:04:43,030 the last class of object in the solar 102 00:04:48,090 --> 00:04:45,460 system we will have completed the 103 00:04:59,150 --> 00:04:48,100 chapter of our initial exploration of 104 00:05:01,760 --> 00:04:59,160 that yes yes yeah why was right no they 105 00:05:04,409 --> 00:05:01,770 the Hubble survey finds an ideal target 106 00:05:07,770 --> 00:05:04,419 the new horizons will be redirected 107 00:05:10,469 --> 00:05:07,780 after it passes Pluto to flyby this 108 00:05:12,480 --> 00:05:10,479 object again finding these is like 109 00:05:15,210 --> 00:05:12,490 trying to find a said Manhattan Island 110 00:05:19,920 --> 00:05:15,220 but imagine Manhattan Island covered in 111 00:05:26,520 --> 00:05:19,930 black velvet four billion miles away and 112 00:05:28,409 --> 00:05:26,530 Hubble found it the almighty Hubble no 113 00:05:31,790 --> 00:05:28,419 that's about our clouds like your away 114 00:05:35,070 --> 00:05:31,800 so unless you invent immortality it's 115 00:05:37,400 --> 00:05:35,080 the I don't want to digress with the 116 00:05:40,110 --> 00:05:37,410 Voyager spacecraft that that sound the 117 00:05:42,950 --> 00:05:40,120 on the way out it'll take it I think 118 00:05:45,600 --> 00:05:42,960 10,000 years to reach the earth clap so 119 00:05:48,780 --> 00:05:45,610 again that's about 50,000 astronomical 120 00:05:51,810 --> 00:05:48,790 units Kuiper belt is no more than five 121 00:05:54,930 --> 00:05:51,820 astronomical units now I wanted to bring 122 00:05:57,450 --> 00:05:54,940 this up because the talk tonight deals 123 00:05:59,850 --> 00:05:57,460 with disks around other stars for 124 00:06:01,010 --> 00:05:59,860 planets are forming so this is a Hubble 125 00:06:02,960 --> 00:06:01,020 picture and nobody 126 00:06:05,839 --> 00:06:02,970 to ink on it they just blocked out the 127 00:06:08,510 --> 00:06:05,849 star but this is a Kuiper belt like disc 128 00:06:10,879 --> 00:06:08,520 around another star and it's really 129 00:06:13,850 --> 00:06:10,889 evidence circumstantial evidence for the 130 00:06:16,159 --> 00:06:13,860 formation of planets around other stars 131 00:06:18,170 --> 00:06:16,169 and that's really the talk tonight and I 132 00:06:20,480 --> 00:06:18,180 think these discs are important they've 133 00:06:23,689 --> 00:06:20,490 only been known about for about 15 years 134 00:06:24,800 --> 00:06:23,699 or so you know if you ask a child where 135 00:06:27,290 --> 00:06:24,810 did they come from they'll say the 136 00:06:31,369 --> 00:06:27,300 hospital but studying the Kuiper belt 137 00:06:34,040 --> 00:06:31,379 discs go back to 4.6 billion years word 138 00:06:36,409 --> 00:06:34,050 of the solar system comes from so we 139 00:06:38,779 --> 00:06:36,419 have a wonderfully of enthusiastic 140 00:06:41,930 --> 00:06:38,789 speaker tonight andrea 141 00:06:43,909 --> 00:06:41,940 ben sati who has specialized in the 142 00:06:46,370 --> 00:06:43,919 chemistry and physics of how planets 143 00:06:49,550 --> 00:06:46,380 form inside these circumstellar disks 144 00:06:52,279 --> 00:06:49,560 he's a postdoctoral fellow here at the 145 00:06:55,370 --> 00:06:52,289 Space Telescope Institute now he got his 146 00:06:58,969 --> 00:06:55,380 PhD from the Institute for technology 147 00:07:00,680 --> 00:06:58,979 and Europe in Zurich Switzerland I 148 00:07:04,879 --> 00:07:00,690 forget the name of that right 149 00:07:07,879 --> 00:07:04,889 close sir Institute for technology in 150 00:07:09,260 --> 00:07:07,889 astronomy he got his master's working at 151 00:07:13,249 --> 00:07:09,270 the European Southern Observatory's 152 00:07:17,749 --> 00:07:13,259 headquarters in Garching Germany and he 153 00:07:25,830 --> 00:07:17,759 got his masters and bachelor's in Italy 154 00:07:55,320 --> 00:07:49,320 Oh is another Kuiper belt I see 100 G hi 155 00:07:57,570 --> 00:07:55,330 hello hello okay so I have different 156 00:08:02,159 --> 00:07:57,580 instruments here I think I need only 157 00:08:05,670 --> 00:08:02,169 this one from now so Frank is not here 158 00:08:09,000 --> 00:08:05,680 tonight but actually he's the inventor 159 00:08:10,770 --> 00:08:09,010 of the name he made up the the title of 160 00:08:13,440 --> 00:08:10,780 this talk building new words in 161 00:08:14,820 --> 00:08:13,450 protoplanetary discs I simply told him 162 00:08:17,250 --> 00:08:14,830 that I was working for information and 163 00:08:20,060 --> 00:08:17,260 we came up with this appealing title and 164 00:08:22,890 --> 00:08:20,070 we did when he told me this this title I 165 00:08:46,460 --> 00:08:22,900 actually felt a bit of vertigo and the 166 00:09:04,860 --> 00:09:00,660 you hear me okay okay so I was saying 167 00:09:07,020 --> 00:09:04,870 that I I was tempted so Frank made up 168 00:09:08,670 --> 00:09:07,030 this this time the title of his talk and 169 00:09:10,290 --> 00:09:08,680 I was telling some wanted to change it 170 00:09:16,560 --> 00:09:10,300 then to narrow it down on the capital of 171 00:09:18,720 --> 00:09:16,570 things on which I am working on but in 172 00:09:23,400 --> 00:09:18,730 the end I decided to keep the challenge 173 00:09:25,680 --> 00:09:23,410 and keep the title for for one reason 174 00:09:27,390 --> 00:09:25,690 mainly I thought about it and for one 175 00:09:31,470 --> 00:09:27,400 reason I decided to keep the title as 176 00:09:34,710 --> 00:09:31,480 broad as it is because of the mystery 177 00:09:37,949 --> 00:09:34,720 I feel attracted to I know that even 178 00:09:38,750 --> 00:09:37,959 with an entire life dedicated to working 179 00:09:44,300 --> 00:09:38,760 on 180 00:09:46,310 --> 00:09:44,310 and yet I feel attracted to it like for 181 00:09:48,680 --> 00:09:46,320 example like Shahrukh Khan's who cannot 182 00:09:51,110 --> 00:09:48,690 stay away from intriguing facts that he 183 00:09:52,850 --> 00:09:51,120 reads on newspapers okay and like 184 00:09:55,280 --> 00:09:52,860 Sherlock Holmes I like to go on the 185 00:09:56,990 --> 00:09:55,290 crime scene to see what what happened 186 00:09:59,810 --> 00:09:57,000 okay 187 00:10:03,020 --> 00:09:59,820 in other words I am an observer I like 188 00:10:06,140 --> 00:10:03,030 to look at facts collect hints and try 189 00:10:10,130 --> 00:10:06,150 to see the story hidden beyond the 190 00:10:14,210 --> 00:10:10,140 appearance of things I think that all of 191 00:10:16,640 --> 00:10:14,220 you understand the kind of investigative 192 00:10:18,920 --> 00:10:16,650 our president talking about because this 193 00:10:21,590 --> 00:10:18,930 is not something for astronomers or for 194 00:10:23,600 --> 00:10:21,600 scientists only otherwise you will not 195 00:10:27,140 --> 00:10:23,610 be here tonight this is something that 196 00:10:29,240 --> 00:10:27,150 we discover in our cells at least at 197 00:10:31,820 --> 00:10:29,250 some point in life at least where we are 198 00:10:36,650 --> 00:10:31,830 kids okay and and in fact astronomers 199 00:10:38,060 --> 00:10:36,660 are a kind of never growing kids but 200 00:10:41,810 --> 00:10:38,070 what is the mystery that I'm talking 201 00:10:47,630 --> 00:10:41,820 about so let's imagine for a moment that 202 00:10:50,360 --> 00:10:47,640 we are Sherlock Holmes it's the morning 203 00:10:52,370 --> 00:10:50,370 and after a delicate British breakfast 204 00:10:56,480 --> 00:10:52,380 we are ready to read the daily 205 00:10:58,880 --> 00:10:56,490 newspapers okay since we are experienced 206 00:11:01,660 --> 00:10:58,890 investigators we know that the news we 207 00:11:04,640 --> 00:11:01,670 can be in big capitals on the front page 208 00:11:07,160 --> 00:11:04,650 they are the least reliable the most 209 00:11:10,040 --> 00:11:07,170 contaminated so as experienced 210 00:11:13,100 --> 00:11:10,050 investigators we go for the news with a 211 00:11:14,990 --> 00:11:13,110 small in the corner those news that are 212 00:11:17,300 --> 00:11:15,000 dedicated a few paragraphs at the end of 213 00:11:18,980 --> 00:11:17,310 the newspaper okay the section that you 214 00:11:20,570 --> 00:11:18,990 would read on if you have a lot of spare 215 00:11:26,210 --> 00:11:20,580 time during the day and be happy because 216 00:11:28,910 --> 00:11:26,220 we are Sherlock Holmes we have not so 217 00:11:32,510 --> 00:11:28,920 today this morning we open the newspaper 218 00:11:37,340 --> 00:11:32,520 and we read a title it title written 219 00:11:40,100 --> 00:11:37,350 small catches our attention a title the 220 00:11:42,950 --> 00:11:40,110 wheels a story the begins in a 221 00:11:45,950 --> 00:11:42,960 breathtaking beauty and then in an 222 00:11:48,230 --> 00:11:45,960 unexpected way unexpected this is this 223 00:11:50,630 --> 00:11:48,240 is for eyes so we immediately go to the 224 00:11:50,990 --> 00:11:50,640 section section Bly at the end of the 225 00:11:57,199 --> 00:11:51,000 news 226 00:12:09,460 --> 00:11:57,209 okay and this is what we will do let me 227 00:12:14,780 --> 00:12:12,590 with increasing telescopic capabilities 228 00:12:17,449 --> 00:12:14,790 it turned out that the interstellar 229 00:12:20,480 --> 00:12:17,459 space is not as black and empty as it 230 00:12:22,910 --> 00:12:20,490 looks to human hands from earth diffuse 231 00:12:25,400 --> 00:12:22,920 gas and dust are present everywhere in 232 00:12:28,220 --> 00:12:25,410 our galaxy we ten use a mission that can 233 00:12:31,579 --> 00:12:28,230 be seen with modern telescopes like the 234 00:12:34,550 --> 00:12:31,589 NASA Hubble Space Telescope these 235 00:12:38,509 --> 00:12:34,560 regions are primarily made of gas 99% in 236 00:12:40,550 --> 00:12:38,519 mass with only 1% is more dust grains it 237 00:12:43,129 --> 00:12:40,560 is from the interplay of gas and dust 238 00:12:46,069 --> 00:12:43,139 and the surrounding radiation that 239 00:12:48,590 --> 00:12:46,079 amazing figures are carved deep into the 240 00:12:50,809 --> 00:12:48,600 interstellar space providing undoubtedly 241 00:12:54,980 --> 00:12:50,819 some of the most beautiful images of the 242 00:12:58,249 --> 00:12:54,990 local universe driven by observational 243 00:13:00,920 --> 00:12:58,259 evidence scientists propose that stars 244 00:13:05,150 --> 00:13:00,930 are formed by collapse of droplets of 245 00:13:07,699 --> 00:13:05,160 material in these regions for reasons 246 00:13:09,769 --> 00:13:07,709 that are not yet fully understood at 247 00:13:11,179 --> 00:13:09,779 some point dense course become 248 00:13:15,220 --> 00:13:11,189 gravitationally unstable and rapidly 249 00:13:17,720 --> 00:13:15,230 collapse in a flattened rotating disc 250 00:13:22,449 --> 00:13:17,730 which in turn a crease material on to 251 00:13:25,389 --> 00:13:22,459 form a star a protostar at the center 252 00:13:29,540 --> 00:13:25,399 the reading sorry 253 00:13:31,999 --> 00:13:29,550 with time disks disappear and the 254 00:13:35,210 --> 00:13:32,009 newborn star is ready for its mature 255 00:13:37,759 --> 00:13:35,220 phases on the main sequence burning 256 00:13:40,280 --> 00:13:37,769 heavier and heavier elements in its core 257 00:13:43,429 --> 00:13:40,290 and eventually releasing them back into 258 00:13:44,840 --> 00:13:43,439 the interstellar space but this is 259 00:13:48,710 --> 00:13:44,850 another story and we shall not get 260 00:13:50,780 --> 00:13:48,720 distracted as it is right now the we 261 00:13:54,170 --> 00:13:50,790 unexpectedly knot is something that was 262 00:13:56,509 --> 00:13:54,180 not previously under focus scientists 263 00:14:01,819 --> 00:13:56,519 proposed that this physics would let us 264 00:14:04,170 --> 00:14:01,829 believe that the surco stellar matter is 265 00:14:06,450 --> 00:14:04,180 quickly accreted onto the star 266 00:14:09,360 --> 00:14:06,460 or dispersed by high-energy radiation 267 00:14:13,139 --> 00:14:09,370 and this has been largely confirmed by 268 00:14:15,200 --> 00:14:13,149 observations but the sequence teller 269 00:14:18,740 --> 00:14:15,210 material does not completely disappear 270 00:14:21,720 --> 00:14:18,750 some spherical bodies solid and gaseous 271 00:14:25,710 --> 00:14:21,730 rotate in orbits flatten on a plane that 272 00:14:27,769 --> 00:14:25,720 resembles the initial disc so at the end 273 00:14:31,260 --> 00:14:27,779 of the star formation process we find 274 00:14:32,970 --> 00:14:31,270 planets the reader could gently remind 275 00:14:34,829 --> 00:14:32,980 us that this is not surprising and then 276 00:14:36,720 --> 00:14:34,839 if that were not true 277 00:14:40,380 --> 00:14:36,730 we would not be here for soon with these 278 00:14:42,360 --> 00:14:40,390 maps nor with any other we would then 279 00:14:44,639 --> 00:14:42,370 gently remind the reader that it was 280 00:14:47,160 --> 00:14:44,649 only yesterday that planets have been 281 00:14:49,889 --> 00:14:47,170 found to be the natural outcome of star 282 00:14:52,050 --> 00:14:49,899 formation and scientists are still 283 00:14:54,570 --> 00:14:52,060 struggling to find a comprehensive way 284 00:14:58,260 --> 00:14:54,580 to make this happen naturally in their 285 00:15:00,540 --> 00:14:58,270 models this is why circumstellar disks 286 00:15:03,660 --> 00:15:00,550 are increasingly dedicated efforts in 287 00:15:06,480 --> 00:15:03,670 astronomical research today to unveil 288 00:15:09,720 --> 00:15:06,490 what they secretly do inside themselves 289 00:15:11,880 --> 00:15:09,730 in order to build new world and such a 290 00:15:14,940 --> 00:15:11,890 variety of words that can be so 291 00:15:17,670 --> 00:15:14,950 different from our own a challenging 292 00:15:20,250 --> 00:15:17,680 task if we consider that since the 293 00:15:22,160 --> 00:15:20,260 beginning this field of research has 294 00:15:25,680 --> 00:15:22,170 been driven by observations and 295 00:15:28,050 --> 00:15:25,690 unexpected discoveries but challenges 296 00:15:30,480 --> 00:15:28,060 and the unexpected are the two pillars 297 00:15:35,310 --> 00:15:30,490 of cutting-edge research and triggers 298 00:15:37,050 --> 00:15:35,320 for investigative Minds so let me now 299 00:15:42,090 --> 00:15:37,060 draw let's now drop the Sherlock Holmes 300 00:15:45,990 --> 00:15:42,100 character and get back into myself if I 301 00:15:50,010 --> 00:15:46,000 can distinguish the two I choose this 302 00:15:51,930 --> 00:15:50,020 article - to set the stage of the of the 303 00:15:54,090 --> 00:15:51,940 topic of the night of the mystery that 304 00:15:56,790 --> 00:15:54,100 we address tonight how planets and not 305 00:16:00,389 --> 00:15:56,800 only planets but worlds can form inside 306 00:16:08,220 --> 00:16:00,399 protoplanetary disks and the crime scene 307 00:16:09,990 --> 00:16:08,230 that we need to go to our second stellar 308 00:16:11,490 --> 00:16:10,000 disk or protoplanet at least likely like 309 00:16:14,130 --> 00:16:11,500 those that we see this beautiful he 310 00:16:15,990 --> 00:16:14,140 image of the of the of the Hubble from 311 00:16:19,140 --> 00:16:16,000 from the Hubble Space Telescope here you 312 00:16:23,550 --> 00:16:19,150 see images and there you see an artist's 313 00:16:26,220 --> 00:16:23,560 impression and so the mystery we address 314 00:16:28,560 --> 00:16:26,230 tonight is a story that begins in a 315 00:16:31,550 --> 00:16:28,570 breathtaking beauty and thence in an 316 00:16:49,920 --> 00:16:47,430 so as a first team let's let's look 317 00:16:52,260 --> 00:16:49,930 first at this at a couple of of things 318 00:16:55,019 --> 00:16:52,270 to understand better what what we read 319 00:16:58,170 --> 00:16:55,029 in the article okay and let's start from 320 00:17:00,000 --> 00:16:58,180 where shallow cones would serve as well 321 00:17:02,579 --> 00:17:00,010 as any astronomer would start where 322 00:17:06,659 --> 00:17:02,589 where when we address a new unknown 323 00:17:08,490 --> 00:17:06,669 problem the library okay my I remember 324 00:17:11,100 --> 00:17:08,500 my PhD supervisor used to tell me that 325 00:17:14,819 --> 00:17:11,110 when he started in astronomy some 25 326 00:17:22,799 --> 00:17:14,829 years ago he used to to go am I going to 327 00:17:25,860 --> 00:17:22,809 - so I still remember then my PhD 328 00:17:30,020 --> 00:17:25,870 supervisor told me that when he started 329 00:17:33,720 --> 00:17:30,030 in astronomy some twenty-five years ago 330 00:17:36,799 --> 00:17:33,730 he used to go regularly to the library 331 00:17:39,630 --> 00:17:36,809 physically and be able to read all 332 00:17:43,640 --> 00:17:39,640 astronomy papers would the deck they 333 00:17:46,380 --> 00:17:43,650 were published worldwide okay now it's 334 00:17:49,230 --> 00:17:46,390 more difficult because something like a 335 00:17:52,080 --> 00:17:49,240 hundred new papers in astronomy every 336 00:17:54,950 --> 00:17:52,090 day so if you spend your time reading 337 00:17:59,880 --> 00:17:54,960 them you spend your life reading them 338 00:18:01,919 --> 00:17:59,890 but now we have a wonderful online tool 339 00:18:05,610 --> 00:18:01,929 which is an online library where we can 340 00:18:09,570 --> 00:18:05,620 search for papers even back in history 341 00:18:11,730 --> 00:18:09,580 using keywords and this is what we are 342 00:18:15,299 --> 00:18:11,740 going to do now okay so let's use two 343 00:18:17,540 --> 00:18:15,309 keywords using the things that we have 344 00:18:20,610 --> 00:18:17,550 that were mentioned in the article 345 00:18:23,280 --> 00:18:20,620 psycho stellar disk and exoplanet okay 346 00:18:26,610 --> 00:18:23,290 in this plot you see the number of 347 00:18:31,039 --> 00:18:26,620 published papers in force lots of years 348 00:18:36,330 --> 00:18:33,960 let's look at exoplanets what happened 349 00:18:37,799 --> 00:18:36,340 at the exoplanet so these are papers 350 00:18:42,389 --> 00:18:37,809 they were published within the planet in 351 00:18:52,409 --> 00:18:42,399 the title sorry but we are going to stay 352 00:18:54,419 --> 00:18:52,419 here for two hours if I don't so this is 353 00:18:56,930 --> 00:18:54,429 what happened in the field of exoplanets 354 00:18:59,820 --> 00:18:56,940 what do we see from here that the 355 00:19:06,620 --> 00:18:59,830 interest in exoplanet has grown 356 00:19:11,700 --> 00:19:10,529 this is what we find okay so while we 357 00:19:14,190 --> 00:19:11,710 see that the interest in exoplanet 358 00:19:15,810 --> 00:19:14,200 hasn't blown along it seems that the 359 00:19:18,210 --> 00:19:15,820 interest the number of publications 360 00:19:20,430 --> 00:19:18,220 interesting circumstellar disk is is not 361 00:19:22,799 --> 00:19:20,440 really growing anymore actually we can 362 00:19:24,930 --> 00:19:22,809 imagine from this become conclude that 363 00:19:27,320 --> 00:19:24,940 the interest in circle stellar disk is 364 00:19:32,220 --> 00:19:27,330 going to die very soon because 365 00:19:34,889 --> 00:19:32,230 exoplanets are the sexy thing now that 366 00:19:37,409 --> 00:19:34,899 we want to look at okay and here is 367 00:19:39,720 --> 00:19:37,419 where an investigative mind is triggered 368 00:19:41,970 --> 00:19:39,730 because maybe we don't have the full 369 00:19:46,560 --> 00:19:41,980 evidence in front of us maybe we are 370 00:19:49,740 --> 00:19:46,570 asking the wrong question you have heard 371 00:19:52,200 --> 00:19:49,750 the day in the title that here I'm 372 00:19:54,509 --> 00:19:52,210 talking about circumstellar disks but 373 00:19:58,019 --> 00:19:54,519 they are now more known with the name 374 00:20:01,649 --> 00:19:58,029 protoplanetary okay and this word was 375 00:20:03,870 --> 00:20:01,659 created to suggest the idea that planets 376 00:20:05,340 --> 00:20:03,880 are formed inside circle solid discs 377 00:20:08,279 --> 00:20:05,350 okay we are talking about the same thing 378 00:20:11,460 --> 00:20:08,289 okay but they are called saku Stella or 379 00:20:13,860 --> 00:20:11,470 protoplanet okay and this idea that 380 00:20:17,009 --> 00:20:13,870 planets are form a circle solid disk is 381 00:20:19,529 --> 00:20:17,019 much older than exoplanets that they did 382 00:20:23,009 --> 00:20:19,539 the discoveries of exoplanets okay and 383 00:20:25,620 --> 00:20:23,019 was born by by considering the an 384 00:20:27,930 --> 00:20:25,630 interesting similarity between the the 385 00:20:30,000 --> 00:20:27,940 orbits of the planets of our own solar 386 00:20:32,820 --> 00:20:30,010 system that are flattened on on a plane 387 00:20:35,789 --> 00:20:32,830 and the first images of protoplanet of 388 00:20:37,590 --> 00:20:35,799 circumstellar disk that where a disk so 389 00:20:41,049 --> 00:20:37,600 flattened on a plane 390 00:20:49,740 --> 00:20:41,059 so now let's look at papers publications 391 00:20:52,900 --> 00:20:49,750 with protoplanetary discs so this is 392 00:20:57,310 --> 00:20:52,910 interesting because it's telling us one 393 00:20:59,049 --> 00:20:57,320 thing well two things first we find what 394 00:21:00,850 --> 00:20:59,059 the article was saying so indeed the 395 00:21:03,549 --> 00:21:00,860 interest in protoplanetary discs 396 00:21:05,710 --> 00:21:03,559 Israelis is increasing and has been 397 00:21:10,230 --> 00:21:05,720 increasing a lot lately okay in the last 398 00:21:13,870 --> 00:21:10,240 two decades and second thing is that 399 00:21:17,020 --> 00:21:13,880 exoplanets seems to be the driving the 400 00:21:21,100 --> 00:21:17,030 driving force shifting the focus from 401 00:21:22,570 --> 00:21:21,110 the origin of stars in the in the world 402 00:21:24,490 --> 00:21:22,580 that silk Estella to the origin of 403 00:21:26,410 --> 00:21:24,500 planets now we are talking about the 404 00:21:28,600 --> 00:21:26,420 same thing but now instead of calling it 405 00:21:30,940 --> 00:21:28,610 circles that we call it protoplanet okay 406 00:21:33,310 --> 00:21:30,950 so this strongly suggest that we see 407 00:21:36,010 --> 00:21:33,320 indeed you see that the rise of the 408 00:21:41,200 --> 00:21:36,020 protoplanetary name the use of the name 409 00:21:45,880 --> 00:21:41,210 is together with okay but now let me ask 410 00:21:47,919 --> 00:21:45,890 you this question if by now if right now 411 00:21:50,950 --> 00:21:47,929 there is a huge interest in exoplanets 412 00:21:54,130 --> 00:21:50,960 and if by now its upper end it's clear 413 00:21:56,919 --> 00:21:54,140 that exoplanets are common around other 414 00:22:04,180 --> 00:21:56,929 stars why should we care how they form 415 00:22:07,630 --> 00:22:04,190 no they simply are and to address this 416 00:22:11,410 --> 00:22:07,640 question let's go let me let me bring 417 00:22:15,640 --> 00:22:11,420 you to the big today back in time to the 418 00:22:18,460 --> 00:22:15,650 time when the curves here stars start to 419 00:22:21,370 --> 00:22:18,470 diverge to the early 1990s when the 420 00:22:23,080 --> 00:22:21,380 first exoplanets were well found here 421 00:22:26,740 --> 00:22:23,090 you find here you see the first two 422 00:22:29,740 --> 00:22:26,750 papers 1992 and 1995 that we are 423 00:22:32,650 --> 00:22:29,750 presenting they the first example 424 00:22:36,820 --> 00:22:32,660 discovers okay and now to understand the 425 00:22:39,250 --> 00:22:36,830 key point of these two papers I want to 426 00:22:41,700 --> 00:22:39,260 do an experiment with you and they need 427 00:22:45,120 --> 00:22:41,710 one or two volunteers 428 00:22:53,590 --> 00:22:45,130 who feel like dr. Watson they want to 429 00:23:10,990 --> 00:22:53,600 play with Rochelle bombs come in even 430 00:23:13,720 --> 00:23:11,000 two people spam there is one test you 431 00:23:26,890 --> 00:23:13,730 have to pass to participate to this test 432 00:23:49,580 --> 00:23:26,900 to this experiment what is this okay you 433 00:23:57,539 --> 00:23:54,870 so this favorite I want to do is to we 434 00:24:01,890 --> 00:23:57,549 have our star this is as you see it's a 435 00:24:12,330 --> 00:24:01,900 star and now we take the material of 436 00:24:14,279 --> 00:24:12,340 which the star is made which is so we 437 00:24:16,019 --> 00:24:14,289 are using the same material to make the 438 00:24:18,810 --> 00:24:16,029 disc because this time is made from the 439 00:24:21,360 --> 00:24:18,820 disk okay so I'm allowed to do that okay 440 00:24:24,060 --> 00:24:21,370 so we use the material of which the star 441 00:24:26,580 --> 00:24:24,070 is made let's do it you you make two 442 00:24:29,820 --> 00:24:26,590 rings one very close one very close so 443 00:24:33,450 --> 00:24:29,830 put it here and the other one as far as 444 00:24:42,659 --> 00:24:33,460 you can to within the limits of this 445 00:24:44,250 --> 00:24:42,669 table that's for this time okay so in 446 00:24:47,100 --> 00:24:44,260 the and so you do this small one you do 447 00:24:51,779 --> 00:24:47,110 the large one doesn't matter if it's not 448 00:24:55,860 --> 00:24:51,789 super okay and please pay attention 449 00:25:01,060 --> 00:24:58,900 so in the meantime I have something also 450 00:25:42,900 --> 00:25:01,070 for the rest of the audience you can you 451 00:25:53,140 --> 00:25:48,610 alright now next step I want you to form 452 00:25:54,490 --> 00:25:53,150 two clans at the two distances from the 453 00:25:56,830 --> 00:25:54,500 start that we have here where we have 454 00:25:58,000 --> 00:25:56,840 material ok using only the material that 455 00:26:23,020 --> 00:25:58,010 we have at that radius 456 00:26:26,020 --> 00:26:23,030 ok so let's do that let's assume the 457 00:26:34,900 --> 00:26:26,030 baby let's assume that plan for measure 458 00:26:37,480 --> 00:26:34,910 works better than this ok now in this 459 00:26:39,760 --> 00:26:37,490 kind of scenario where would you form 460 00:26:44,710 --> 00:26:39,770 the most massive planet and where would 461 00:26:50,169 --> 00:26:44,720 you form the least massive planet for 462 00:27:07,740 --> 00:26:50,179 the ratio for the radius Y you can also 463 00:27:12,250 --> 00:27:10,870 wait wait wait don't go too far let's go 464 00:27:16,450 --> 00:27:12,260 let's go step by step 465 00:27:18,310 --> 00:27:16,460 okay so in if this were a scaled version 466 00:27:18,940 --> 00:27:18,320 of our solar system where would you from 467 00:27:26,490 --> 00:27:18,950 Jupiter 468 00:27:32,710 --> 00:27:26,500 well would you form mercury or wonderful 469 00:27:35,400 --> 00:27:32,720 now push back now let's look at the 470 00:27:38,340 --> 00:27:35,410 90-95 what they differ 471 00:27:43,270 --> 00:27:38,350 they found the jupiter-mass companion 472 00:27:47,530 --> 00:27:43,280 well inside the orbit of mercury this 473 00:27:49,750 --> 00:27:47,540 was very unexpected I can tell you that 474 00:27:53,410 --> 00:27:49,760 I had the pleasure you stay here 475 00:27:57,130 --> 00:27:53,420 the pleasure of two personal meetings 476 00:27:58,840 --> 00:27:57,140 with this guy here it's from Switzerland 477 00:28:02,230 --> 00:27:58,850 I did my business bits alone for a 478 00:28:05,500 --> 00:28:02,240 reason well imagine there and then a 479 00:28:10,690 --> 00:28:05,510 very heard from him the story and he the 480 00:28:13,270 --> 00:28:10,700 solar to be scorned and he has a 481 00:28:15,880 --> 00:28:13,280 wonderful story to tell about finding 482 00:28:18,580 --> 00:28:15,890 something unexpected something that for 483 00:28:22,450 --> 00:28:18,590 the theories at that time was completely 484 00:28:24,790 --> 00:28:22,460 impossible was impossible such that when 485 00:28:29,440 --> 00:28:24,800 they started to have the idea of what 486 00:28:33,520 --> 00:28:29,450 they were finding was at the time he was 487 00:28:35,650 --> 00:28:33,530 very young he was worried because he 488 00:28:38,020 --> 00:28:35,660 said this is not possible if it cannot 489 00:28:39,730 --> 00:28:38,030 be a Jupiter around the Stars so close 490 00:28:41,550 --> 00:28:39,740 to the star it's impossible nobody 491 00:28:45,760 --> 00:28:41,560 nobody would believe that because 492 00:28:47,470 --> 00:28:45,770 theories cannot explain that okay but I 493 00:28:50,920 --> 00:28:47,480 need turned out to be true and now we 494 00:28:51,860 --> 00:28:50,930 have many ok let's go back to our 495 00:29:02,000 --> 00:28:51,870 experiment 496 00:29:05,120 --> 00:29:02,010 now so now let's say that at some point 497 00:29:48,120 --> 00:29:05,130 the star explodes in a supernova what do 498 00:29:48,130 --> 00:30:24,290 this is what 499 00:30:31,020 --> 00:30:28,290 so let's move 1992 paper what did they 500 00:30:34,830 --> 00:30:31,030 find they found not not not one but two 501 00:30:37,590 --> 00:30:34,840 planets where around a pulsar a pulsar 502 00:30:40,200 --> 00:30:37,600 is the neutron star the neutron remnant 503 00:30:46,650 --> 00:30:40,210 star after supernova supernova explosion 504 00:30:49,320 --> 00:30:46,660 and even back then so you cannot say 505 00:30:50,970 --> 00:30:49,330 well optimistically I was they are far 506 00:30:53,220 --> 00:30:50,980 enough out that they don't feel the 507 00:30:55,080 --> 00:30:53,230 supernova supernova explosion they were 508 00:30:58,830 --> 00:30:55,090 very close inside the orbit of Earth 509 00:31:02,490 --> 00:30:58,840 they would be destroyed for sure so what 510 00:31:05,310 --> 00:31:02,500 was what is the point that I that I for 511 00:31:09,480 --> 00:31:05,320 which we we we made the this experiment 512 00:31:11,880 --> 00:31:09,490 I made to make here one thing that since 513 00:31:13,980 --> 00:31:11,890 the very beginning the field of 514 00:31:19,140 --> 00:31:13,990 exoplanet research has been the reign of 515 00:31:22,080 --> 00:31:19,150 the unexpected okay and it is so even 516 00:31:26,640 --> 00:31:22,090 now let's look for example at this plot 517 00:31:29,130 --> 00:31:26,650 that is more recent this is 2013 when we 518 00:31:31,560 --> 00:31:29,140 see a representation of the population 519 00:31:34,410 --> 00:31:31,570 of planets that the exoplanets that we 520 00:31:42,269 --> 00:31:34,420 have been detected so far this is going 521 00:31:49,289 --> 00:31:45,580 so even here you see that the known 522 00:31:52,570 --> 00:31:49,299 population of exoplanets we have a 523 00:31:54,820 --> 00:31:52,580 population here of planets that are more 524 00:31:57,489 --> 00:31:54,830 massive than Earth this is the mass and 525 00:32:00,700 --> 00:31:57,499 this is the peer proportion today they 526 00:32:02,739 --> 00:32:00,710 are the distance from the star okay so 527 00:32:05,889 --> 00:32:02,749 this planets here are more massive than 528 00:32:07,629 --> 00:32:05,899 Earth but close the ring and this kind 529 00:32:09,190 --> 00:32:07,639 of super day they are called super 530 00:32:11,320 --> 00:32:09,200 Earths because they are more massive and 531 00:32:13,269 --> 00:32:11,330 they seem to be really the rule in plan 532 00:32:17,349 --> 00:32:13,279 formation it seems that every EXO 533 00:32:19,029 --> 00:32:17,359 planetary system has one okay and we 534 00:32:21,519 --> 00:32:19,039 have a population also of Jupiter's 535 00:32:24,039 --> 00:32:21,529 which are called hot Jupiters well 536 00:32:27,129 --> 00:32:24,049 especially this one that are closer win 537 00:32:29,889 --> 00:32:27,139 again then our Jupiter okay here we have 538 00:32:33,099 --> 00:32:29,899 our Jupiter here we have been a very 539 00:32:34,899 --> 00:32:33,109 nice honor okay and this is just 540 00:32:38,109 --> 00:32:34,909 considering two properties of the 541 00:32:42,149 --> 00:32:38,119 planets the mass and the distance from 542 00:32:44,859 --> 00:32:42,159 the star okay many scientists say that 543 00:32:48,009 --> 00:32:44,869 when we will be able to study more 544 00:32:51,219 --> 00:32:48,019 details the composition of the planets 545 00:32:54,009 --> 00:32:51,229 of the atmospheres and the bulk 546 00:32:57,899 --> 00:32:54,019 composition of the of the core we will 547 00:33:00,849 --> 00:32:57,909 be very likely surprised by unexpected 548 00:33:02,859 --> 00:33:00,859 discoveries at this point we expect to 549 00:33:06,249 --> 00:33:02,869 be surprised by the unexpected in this 550 00:33:08,820 --> 00:33:06,259 field okay so let me answer now the 551 00:33:10,930 --> 00:33:08,830 question why should we care about 552 00:33:13,719 --> 00:33:10,940 protoplanetary discs why should we study 553 00:33:15,999 --> 00:33:13,729 them because we are surprised by the 554 00:33:19,239 --> 00:33:16,009 unexpected discoveries in the exoplanet 555 00:33:22,210 --> 00:33:19,249 field and so we would like to understand 556 00:33:24,580 --> 00:33:22,220 how we can form such a variety of 557 00:33:26,889 --> 00:33:24,590 different exoplanets as well as 558 00:33:32,339 --> 00:33:26,899 understand how our own planets and our 559 00:33:37,930 --> 00:33:36,159 let's now go step by step what do we 560 00:33:44,560 --> 00:33:37,940 know about the planet formation process 561 00:33:51,140 --> 00:33:48,590 from the composition okay let's look at 562 00:33:55,820 --> 00:33:51,150 our the most familiar case of our solar 563 00:33:59,360 --> 00:33:55,830 system we have the star the Sun mostly 564 00:34:01,970 --> 00:33:59,370 made by hydrogen and helium and the the 565 00:34:03,530 --> 00:34:01,980 gas giants in our solar system as well 566 00:34:06,980 --> 00:34:03,540 they are mostly made by hydrogen and 567 00:34:10,330 --> 00:34:06,990 helium ok so our little experiment that 568 00:34:15,950 --> 00:34:10,340 we did here see it's a simplified 569 00:34:18,169 --> 00:34:15,960 version for me might have probably 570 00:34:22,790 --> 00:34:18,179 worked ok we are using the same material 571 00:34:23,780 --> 00:34:22,800 to form big planets in the disk ok but 572 00:34:26,900 --> 00:34:23,790 we have a problem 573 00:34:30,470 --> 00:34:26,910 for these planets here their composition 574 00:34:34,190 --> 00:34:30,480 is instead is very dissimilar from this 575 00:34:37,820 --> 00:34:34,200 stuff so if the disk has the same 576 00:34:39,919 --> 00:34:37,830 composition this planets are peculiar 577 00:34:41,930 --> 00:34:39,929 because they are mainly first they are 578 00:34:46,030 --> 00:34:41,940 mainly solid and they they they have a 579 00:34:49,159 --> 00:34:46,040 composition that is mostly made by 580 00:34:54,169 --> 00:34:49,169 compounds of iron oxygen silicon and 581 00:34:56,180 --> 00:34:54,179 magnesium okay in in in in short it they 582 00:35:01,040 --> 00:34:56,190 are mainly solid this is the evident 583 00:35:04,250 --> 00:35:01,050 okay gas giants solid rocky if you think 584 00:35:09,320 --> 00:35:04,260 that this approach is trivial to start 585 00:35:10,820 --> 00:35:09,330 from the bulk composition ok please 586 00:35:13,550 --> 00:35:10,830 consider that this is what we are still 587 00:35:15,890 --> 00:35:13,560 doing now with exoplanets this is a very 588 00:35:17,900 --> 00:35:15,900 recent paper where we have the planet 589 00:35:20,540 --> 00:35:17,910 the planet radius here in the planet 590 00:35:26,060 --> 00:35:20,550 Mars on this axis ok this this one is a 591 00:35:28,670 --> 00:35:26,070 zooming in this the plot when we are 592 00:35:32,390 --> 00:35:28,680 able to measure the mass and the radius 593 00:35:35,650 --> 00:35:32,400 of an exoplanet we can measure a mean 594 00:35:39,230 --> 00:35:35,660 density mass divided by the volume and 595 00:35:41,630 --> 00:35:39,240 from the mean density we can estimate 596 00:35:44,720 --> 00:35:41,640 the bulk composition as if the planet 597 00:35:47,480 --> 00:35:44,730 was made by a single thing okay so for 598 00:35:49,640 --> 00:35:47,490 example we can see a planet made of 599 00:35:50,820 --> 00:35:49,650 water the time of water would lie on 600 00:35:54,090 --> 00:35:50,830 this curve depend 601 00:35:56,400 --> 00:35:54,100 on the mass and they reduce okay Oliver 602 00:35:59,820 --> 00:35:56,410 Oliver I know I run eccentric setter 603 00:36:02,310 --> 00:35:59,830 here we have for example the in this 604 00:36:05,790 --> 00:36:02,320 paper they were presenting a discovery 605 00:36:09,000 --> 00:36:05,800 of one of the most earth-like planets in 606 00:36:11,280 --> 00:36:09,010 terms of bulk composition okay you see 607 00:36:14,490 --> 00:36:11,290 that the planets that they found is here 608 00:36:16,800 --> 00:36:14,500 Earth and Venus okay and so it's it's 609 00:36:23,490 --> 00:36:16,810 the closest compared to other kepler 610 00:36:25,530 --> 00:36:23,500 planet okay so historically and 611 00:36:30,390 --> 00:36:25,540 classically the problem of planet 612 00:36:34,200 --> 00:36:30,400 formation is a problem of solids so the 613 00:36:36,650 --> 00:36:34,210 property to build bodies of at least the 614 00:36:39,000 --> 00:36:36,660 kilometers inside a kilometer in size 615 00:36:40,620 --> 00:36:39,010 starting from the dust grains that at 616 00:36:42,510 --> 00:36:40,630 the beginning of the story we said in 617 00:36:44,160 --> 00:36:42,520 the planet formation regions in this 618 00:36:47,700 --> 00:36:44,170 nebula planet formation which is a well 619 00:36:51,180 --> 00:36:47,710 that we observe the the size of this 620 00:36:53,730 --> 00:36:51,190 dust grains that we observe there is one 621 00:36:57,540 --> 00:36:53,740 micron or less 10 to the minus 6 meters 622 00:37:05,070 --> 00:36:57,550 okay so this is a jump of at least nine 623 00:37:06,900 --> 00:37:05,080 orders of magnitude okay in size think 624 00:37:10,710 --> 00:37:06,910 for example of going to the to the beach 625 00:37:13,170 --> 00:37:10,720 and if you take sand of grain it's the 626 00:37:16,260 --> 00:37:13,180 it's even more than the jump from that 627 00:37:19,380 --> 00:37:16,270 send of grain and and earth even more 628 00:37:23,460 --> 00:37:19,390 than that because grains here are 629 00:37:28,440 --> 00:37:23,470 smaller than the same weights so we are 630 00:37:31,080 --> 00:37:28,450 just history yes because we know of 631 00:37:33,180 --> 00:37:31,090 thousands of exoplanets but we still 632 00:37:37,160 --> 00:37:33,190 haven't figured out the details of how 633 00:37:41,220 --> 00:37:37,170 this job happens of this process happens 634 00:37:44,130 --> 00:37:41,230 what we know however is that at least 635 00:37:46,850 --> 00:37:44,140 the first step happens in protoplanetary 636 00:37:49,860 --> 00:37:46,860 disk in circumstellar disks because 637 00:37:52,620 --> 00:37:49,870 scientists have been able to measure the 638 00:37:56,190 --> 00:37:52,630 size of dust grains in these discs and 639 00:37:59,100 --> 00:37:56,200 found one millimeter one centimeter okay 640 00:38:01,230 --> 00:37:59,110 so it's it's it's an increase of three 641 00:38:03,150 --> 00:38:01,240 four orders of magnitude and I've been 642 00:38:03,569 --> 00:38:03,160 working when I was in Germany these oh I 643 00:38:06,539 --> 00:38:03,579 was 644 00:38:08,749 --> 00:38:06,549 on this this field measuring the the 645 00:38:12,569 --> 00:38:08,759 signs of the quincy protoplanetary disk 646 00:38:15,959 --> 00:38:12,579 it's a first step and yet we still have 647 00:38:24,089 --> 00:38:15,969 to grow at least six orders of magnitude 648 00:38:27,150 --> 00:38:24,099 more good so i said this is still an 649 00:38:29,940 --> 00:38:27,160 unsolved mystery you know strong me but 650 00:38:32,069 --> 00:38:29,950 huh is it possible that I mean again we 651 00:38:35,940 --> 00:38:32,079 know of so many exoplanets and we still 652 00:38:39,059 --> 00:38:35,950 don't know of this which is like if you 653 00:38:42,359 --> 00:38:39,069 cannot grow this the solids you cannot 654 00:38:45,809 --> 00:38:42,369 be black we we still don't know because 655 00:38:48,920 --> 00:38:45,819 of due to problems mainly the first 656 00:38:52,620 --> 00:38:48,930 problem is a problem of observations 657 00:38:54,599 --> 00:38:52,630 while gas is mainly optically thin in 658 00:38:56,519 --> 00:38:54,609 these regions okay this is the artists 659 00:39:00,150 --> 00:38:56,529 impression of a protoplanetary disk okay 660 00:39:01,789 --> 00:39:00,160 so while gas is primarily optically thin 661 00:39:04,620 --> 00:39:01,799 so we can see through it 662 00:39:07,189 --> 00:39:04,630 duster is instead of instead of túcume 663 00:39:11,609 --> 00:39:07,199 thick so we cannot see inside the disk 664 00:39:13,319 --> 00:39:11,619 exactly where planets are formed okay to 665 00:39:15,900 --> 00:39:13,329 give you an analogy imagine that you are 666 00:39:18,269 --> 00:39:15,910 driving in the fog and you are trying to 667 00:39:21,539 --> 00:39:18,279 guess if what you have in front of you 668 00:39:24,120 --> 00:39:21,549 is a car a motorcycle or a deer okay 669 00:39:27,239 --> 00:39:24,130 for the same reason in protoplanetary 670 00:39:30,420 --> 00:39:27,249 disk we even though the small dust 671 00:39:32,870 --> 00:39:30,430 grains are small implants that are 672 00:39:35,640 --> 00:39:32,880 forming there are possibly already big 673 00:39:38,910 --> 00:39:35,650 they the opacity is dominated by the 674 00:39:41,069 --> 00:39:38,920 small grains and so we see only do only 675 00:39:44,279 --> 00:39:41,079 them and we cannot see the big bodies 676 00:39:47,099 --> 00:39:44,289 okay and all consider in addition to 677 00:39:50,219 --> 00:39:47,109 that that given the distance of these 678 00:39:52,199 --> 00:39:50,229 disks from Arthur they look to our eyes 679 00:39:53,489 --> 00:39:52,209 very small in the sky like in these 680 00:39:58,219 --> 00:39:53,499 images from the Hubble Space Telescope 681 00:40:02,189 --> 00:39:58,229 ok and what we are trying to find to see 682 00:40:04,109 --> 00:40:02,199 forming planets inside them at most a 683 00:40:08,430 --> 00:40:04,119 hundred thousand times smaller than 684 00:40:11,730 --> 00:40:08,440 these blobs ok so no way 685 00:40:14,150 --> 00:40:11,740 but I said that this moon disgraces that 686 00:40:16,800 --> 00:40:14,160 became measure know the size I said 687 00:40:19,050 --> 00:40:16,810 stromer's have been able to measure the 688 00:40:21,840 --> 00:40:19,060 signs of the Samantha's grains for the 689 00:40:23,790 --> 00:40:21,850 same reason why did the small that's why 690 00:40:27,570 --> 00:40:23,800 the small particles in the form they 691 00:40:30,090 --> 00:40:27,580 dominate in opacity okay and for example 692 00:40:33,780 --> 00:40:30,100 with the VLE in New Mexico or the Alma 693 00:40:35,550 --> 00:40:33,790 on unmanned chillin nowadays we are able 694 00:40:37,560 --> 00:40:35,560 to measure the thermal emission from 695 00:40:39,510 --> 00:40:37,570 this model screens and measure this and 696 00:40:44,520 --> 00:40:39,520 estimate their Sciences okay you find 697 00:40:48,510 --> 00:40:44,530 again the K visa has for some 698 00:40:51,810 --> 00:40:48,520 microgreens in the nebula second problem 699 00:40:54,780 --> 00:40:51,820 we have the chroming of timescales so 700 00:40:57,180 --> 00:40:54,790 one transformation happens very very 701 00:41:01,190 --> 00:40:57,190 quickly it's very fast compared to the 702 00:41:04,530 --> 00:41:01,200 to the lifetime of star it's very slow 703 00:41:07,070 --> 00:41:04,540 compared to our lifetime okay so we 704 00:41:09,710 --> 00:41:07,080 would have to leave 10000 times an 705 00:41:13,680 --> 00:41:09,720 entire human life to be able to follow 706 00:41:18,060 --> 00:41:13,690 planet formation a planet forming okay 707 00:41:21,840 --> 00:41:18,070 all the stages so we have to two ways 708 00:41:24,360 --> 00:41:21,850 out when when we can know when we cannot 709 00:41:27,330 --> 00:41:24,370 directly see what we are looking for 710 00:41:29,340 --> 00:41:27,340 either we we try to imagine it to in 711 00:41:33,810 --> 00:41:29,350 making models we try to imagine how that 712 00:41:35,670 --> 00:41:33,820 could happen or we try to look at the 713 00:41:39,180 --> 00:41:35,680 same object but in different phases of 714 00:41:40,820 --> 00:41:39,190 evolution okay and then we try to 715 00:41:43,200 --> 00:41:40,830 connect the points and build a story 716 00:41:44,250 --> 00:41:43,210 okay and these two approaches the 717 00:41:46,200 --> 00:41:44,260 theoretical approach and the 718 00:41:48,210 --> 00:41:46,210 observational approach are both are both 719 00:41:52,230 --> 00:41:48,220 fundamental and they sustain and help 720 00:41:53,010 --> 00:41:52,240 each other to build the the story of 721 00:41:56,090 --> 00:41:53,020 planet formation 722 00:41:59,760 --> 00:41:56,100 okay let's look for example at how 723 00:42:03,630 --> 00:41:59,770 theories theoretical models trying to 724 00:42:06,630 --> 00:42:03,640 explain how we can grow dustin disks 725 00:42:09,000 --> 00:42:06,640 from the dust from from the small sizes 726 00:42:12,180 --> 00:42:09,010 of 1 micron as i said 10 to the minus 6 727 00:42:13,440 --> 00:42:12,190 meters up to planet sizes of more than 728 00:42:16,290 --> 00:42:13,450 economic ok 729 00:42:17,920 --> 00:42:16,300 this is from a recent review where a 730 00:42:20,829 --> 00:42:17,930 number of models are put 731 00:42:26,079 --> 00:42:20,839 gather you know the twist plain how it 732 00:42:28,690 --> 00:42:26,089 may be possible to to to climb this 733 00:42:30,849 --> 00:42:28,700 ladder in Sciences and go for dust two 734 00:42:34,059 --> 00:42:30,859 planets okay in in the in the so called 735 00:42:37,390 --> 00:42:34,069 the core accretion scenario so I cannot 736 00:42:40,930 --> 00:42:37,400 go into the details here but this is to 737 00:42:43,990 --> 00:42:40,940 give you an idea that we have we have at 738 00:42:46,690 --> 00:42:44,000 least a few ideas how with following 739 00:42:49,030 --> 00:42:46,700 steps ok different different processes 740 00:42:52,359 --> 00:42:49,040 one after the other or probably 741 00:42:55,030 --> 00:42:52,369 happening the same time the different 742 00:42:56,740 --> 00:42:55,040 Vaidya in the disk again we can go from 743 00:43:00,370 --> 00:42:56,750 dust to to two planets okay 744 00:43:02,620 --> 00:43:00,380 the first step this one number one that 745 00:43:06,309 --> 00:43:02,630 that brings the dust from from here to 746 00:43:09,339 --> 00:43:06,319 millimeter in sizes is believed to be 747 00:43:11,410 --> 00:43:09,349 the one responsible for the emission 748 00:43:14,109 --> 00:43:11,420 that we see with interferometers as i 749 00:43:17,530 --> 00:43:14,119 said before okay so the millimeter sized 750 00:43:19,690 --> 00:43:17,540 grains that we measure in the be 751 00:43:21,760 --> 00:43:19,700 detecting in protoplanetary disk are 752 00:43:25,059 --> 00:43:21,770 probably formed by speaking of small 753 00:43:27,579 --> 00:43:25,069 part okay for the rest the the next 754 00:43:29,470 --> 00:43:27,589 steps are very much still unconstrained 755 00:43:32,319 --> 00:43:29,480 and a mostly theoretical and they are 756 00:43:34,180 --> 00:43:32,329 very difficult to go through a classical 757 00:43:38,289 --> 00:43:34,190 problem this scenario is for example 758 00:43:40,270 --> 00:43:38,299 they so-called meter-sized earlier in 759 00:43:44,260 --> 00:43:40,280 this models it is expected that the soon 760 00:43:46,930 --> 00:43:44,270 as dust grains stick together and they 761 00:43:50,500 --> 00:43:46,940 grow in sizes enough and they reach the 762 00:43:52,990 --> 00:43:50,510 meter one meter inside as an order of 763 00:43:55,660 --> 00:43:53,000 magnitude at one you the distance of 764 00:43:58,839 --> 00:43:55,670 Earth from the Sun they would start to 765 00:44:00,789 --> 00:43:58,849 feel a gas drag that would such that 766 00:44:04,359 --> 00:44:00,799 they would be sucked onto the star very 767 00:44:06,370 --> 00:44:04,369 quickly okay so we have a problem of 768 00:44:08,440 --> 00:44:06,380 time scales here because the the 769 00:44:11,020 --> 00:44:08,450 material of which planets are made need 770 00:44:14,500 --> 00:44:11,030 to stay in the disk long enough for the 771 00:44:16,089 --> 00:44:14,510 planets to to be to be made okay if you 772 00:44:18,970 --> 00:44:16,099 suck all the material to start to 773 00:44:21,740 --> 00:44:18,980 quickly nothing is left no then you 774 00:44:24,740 --> 00:44:21,750 cannot from the planet 775 00:44:29,930 --> 00:44:24,750 but with this with these other 776 00:44:32,510 --> 00:44:29,940 mechanisms here there is the hypothesis 777 00:44:35,180 --> 00:44:32,520 that there can't that there are over 778 00:44:38,330 --> 00:44:35,190 densities in over densities of on 779 00:44:45,010 --> 00:44:38,340 material in disks okay or the so called 780 00:44:53,420 --> 00:44:49,880 and once the the planet did these solids 781 00:44:56,690 --> 00:44:53,430 bodies grow enough okay at some point 782 00:44:58,520 --> 00:44:56,700 gravity kicks in strongly and so all the 783 00:45:01,520 --> 00:44:58,530 smaller bodies are fitted onto this 784 00:45:03,770 --> 00:45:01,530 planet a similar protoplanet and at some 785 00:45:05,630 --> 00:45:03,780 point also also and also the gas 786 00:45:08,990 --> 00:45:05,640 participate with this flow so that you 787 00:45:11,780 --> 00:45:09,000 can it is expected that you can build a 788 00:45:15,020 --> 00:45:11,790 rocky planet with also another gases 789 00:45:18,440 --> 00:45:15,030 atmosphere okay and now very recently 790 00:45:22,370 --> 00:45:18,450 this is of the last few years these dust 791 00:45:24,920 --> 00:45:22,380 traps start to be seen so they they may 792 00:45:27,500 --> 00:45:24,930 they may show us that they did indeed 793 00:45:28,970 --> 00:45:27,510 some kind of things some of these models 794 00:45:30,440 --> 00:45:28,980 that proposed these dust traps are 795 00:45:32,089 --> 00:45:30,450 really happening in viscous so to 796 00:45:35,510 --> 00:45:32,099 allowed to jump from one side to the 797 00:45:38,120 --> 00:45:35,520 other and then okay for example this 798 00:45:44,120 --> 00:45:38,130 observation is from Alma this is the 799 00:45:48,400 --> 00:45:44,130 location of they detected millimeter 800 00:45:50,510 --> 00:45:48,410 sized grains only in this vision okay 801 00:45:54,800 --> 00:45:50,520 showing that these grains are not 802 00:45:58,520 --> 00:45:54,810 distributed on on a disk as ingeniously 803 00:46:01,670 --> 00:45:58,530 okay as one would expect but they are 804 00:46:04,609 --> 00:46:01,680 sort of trapped by some mechanism in 805 00:46:06,680 --> 00:46:04,619 that region and these regions called the 806 00:46:08,780 --> 00:46:06,690 straps are believed to be regions of 807 00:46:12,020 --> 00:46:08,790 efficient planet formation because they 808 00:46:14,900 --> 00:46:12,030 you bring solids on on a smaller portion 809 00:46:20,450 --> 00:46:14,910 of the disk and and you you increase the 810 00:46:24,980 --> 00:46:20,460 probability of interactions and and the 811 00:46:28,040 --> 00:46:24,990 build-up of larger bodies okay now so 812 00:46:29,300 --> 00:46:28,050 while this first step is observed these 813 00:46:33,190 --> 00:46:29,310 intermediate steps 814 00:46:37,070 --> 00:46:33,200 maybe they start to be observed an 815 00:46:39,650 --> 00:46:37,080 Australian at the very end the final 816 00:46:43,240 --> 00:46:39,660 accretion of gas and material on the DS 817 00:46:49,190 --> 00:46:43,250 and on the plan on the protoplanet 818 00:46:52,070 --> 00:46:49,200 is only very very recently that we 819 00:46:54,560 --> 00:46:52,080 started to see also the last steps and 820 00:46:57,800 --> 00:46:54,570 this is a very exciting observations 821 00:47:01,460 --> 00:46:57,810 that it's from was published in 2013 822 00:47:03,830 --> 00:47:01,470 actually Sasha once he was a colleague 823 00:47:08,000 --> 00:47:03,840 of mine at the ETH in Zurich in 824 00:47:10,970 --> 00:47:08,010 Switzerland so what they were they 825 00:47:14,450 --> 00:47:10,980 showed here this is an op Hubble image 826 00:47:17,540 --> 00:47:14,460 of this protoplanetary disc they started 827 00:47:19,730 --> 00:47:17,550 to detect kind of point like not not 828 00:47:22,430 --> 00:47:19,740 exactly point like plane by small 829 00:47:25,310 --> 00:47:22,440 sources of emission inside the disc 830 00:47:28,780 --> 00:47:25,320 still embedded ok and they interpret 831 00:47:32,000 --> 00:47:28,790 these these observations as observing 832 00:47:35,510 --> 00:47:32,010 protoplanets where the disc material is 833 00:47:38,840 --> 00:47:35,520 still tweeting ok onto the protoplanet 834 00:47:42,140 --> 00:47:38,850 and these new observations are starting 835 00:47:47,030 --> 00:47:42,150 to connect the two ends of the story 836 00:47:49,880 --> 00:47:47,040 that until couple of years ago were the 837 00:47:53,150 --> 00:47:49,890 only things we have see coastal discs 838 00:47:55,370 --> 00:47:53,160 and exoplanet okay in between again the 839 00:47:57,650 --> 00:47:55,380 stories very still very unknown because 840 00:48:00,230 --> 00:47:57,660 we cannot see inside discs it seems that 841 00:48:02,390 --> 00:48:00,240 we start in some cases to be able to see 842 00:48:04,250 --> 00:48:02,400 also the emission of some protoplanets 843 00:48:06,140 --> 00:48:04,260 this is still a candidate okay it's not 844 00:48:08,630 --> 00:48:06,150 confirmed yet but I believe that 845 00:48:11,500 --> 00:48:08,640 observations like this will will 846 00:48:16,070 --> 00:48:11,510 increase in number in the near future 847 00:48:19,460 --> 00:48:16,080 ok let's say that now we are able to 848 00:48:21,530 --> 00:48:19,470 overcome the problems and the barriers 849 00:48:23,060 --> 00:48:21,540 that are in our theoretical 850 00:48:29,260 --> 00:48:23,070 understanding and we're able to form 851 00:48:41,680 --> 00:48:35,020 still we don't have yet 852 00:48:44,380 --> 00:48:41,690 planets okay the next step from rocky 853 00:48:46,930 --> 00:48:44,390 balls and define rocky balls to planets 854 00:48:51,310 --> 00:48:46,940 let's address the composition in a bit 855 00:48:55,140 --> 00:48:51,320 in more details okay and let's look 856 00:48:58,300 --> 00:48:55,150 again at our solar system in this scale 857 00:49:00,250 --> 00:48:58,310 representation one of the first things 858 00:49:03,670 --> 00:49:00,260 that struck me when I when I look at 859 00:49:10,090 --> 00:49:03,680 this representation is what you see 860 00:49:16,470 --> 00:49:10,100 immediately so gas giants rocky planets 861 00:49:20,770 --> 00:49:16,480 in rocky planets small gas giants big 862 00:49:22,600 --> 00:49:20,780 there are solid bodies all over the the 863 00:49:24,370 --> 00:49:22,610 solar system okay we heard them even 864 00:49:26,380 --> 00:49:24,380 into in the introduction okay all over 865 00:49:29,050 --> 00:49:26,390 even in the outer regions but as far as 866 00:49:34,570 --> 00:49:29,060 planets are concerned the rocky planets 867 00:49:40,960 --> 00:49:34,580 are the gas giants around so there seems 868 00:49:42,220 --> 00:49:40,970 to be something there between the rocky 869 00:49:46,510 --> 00:49:42,230 and the giant it seems to give 870 00:49:49,359 --> 00:49:46,520 discontinuity some critical change 871 00:49:52,120 --> 00:49:49,369 between the inside and the outside so 872 00:49:54,940 --> 00:49:52,130 the simple idea that this visualization 873 00:49:59,859 --> 00:49:54,950 seems to suggest was proposed in a paper 874 00:50:02,200 --> 00:49:59,869 in 1981 where and here I'm showing the 875 00:50:03,910 --> 00:50:02,210 key figure where we have the density of 876 00:50:08,080 --> 00:50:03,920 material in the disk and the distance 877 00:50:10,120 --> 00:50:08,090 from the Sun where any spill an 878 00:50:13,060 --> 00:50:10,130 experiment similar to what we did here 879 00:50:15,400 --> 00:50:13,070 but reversed was done which is to take 880 00:50:17,650 --> 00:50:15,410 the mass that is nowadays in the planet 881 00:50:21,960 --> 00:50:17,660 okay in our solar system planets and 882 00:50:24,400 --> 00:50:21,970 spread it all the rings of material 883 00:50:27,250 --> 00:50:24,410 assuming that every planet contributes 884 00:50:30,310 --> 00:50:27,260 only to enamels and at its distance on 885 00:50:32,340 --> 00:50:30,320 the star from the Sun okay so to build a 886 00:50:34,930 --> 00:50:32,350 representation of what our own 887 00:50:38,650 --> 00:50:34,940 protoplanetary disk would probably 888 00:50:41,150 --> 00:50:38,660 possibly have looked like and what they 889 00:50:44,329 --> 00:50:41,160 what he found 890 00:50:46,880 --> 00:50:44,339 is a discontinued 891 00:50:49,069 --> 00:50:46,890 okay this is the density of material and 892 00:50:51,349 --> 00:50:49,079 you see but if you connect the points 893 00:50:54,289 --> 00:50:51,359 here we have a discontinuity between the 894 00:50:58,279 --> 00:50:54,299 rocky planets and the giant planet and 895 00:51:00,829 --> 00:50:58,289 this discontinuity was in the in that 896 00:51:04,370 --> 00:51:00,839 paper attributed to a so called snow 897 00:51:06,559 --> 00:51:04,380 line as which is the line marking the 898 00:51:11,620 --> 00:51:06,569 separation between regions where water 899 00:51:14,150 --> 00:51:11,630 is in the is in the is in the ice phase 900 00:51:16,039 --> 00:51:14,160 outside of this line and in the gas 901 00:51:18,410 --> 00:51:16,049 phase inside because of the temperature 902 00:51:20,630 --> 00:51:18,420 okay when the temperature that decreases 903 00:51:24,049 --> 00:51:20,640 with the distance from the star drops 904 00:51:26,029 --> 00:51:24,059 enough so to water to freeze out then 905 00:51:27,529 --> 00:51:26,039 you have on the ice on one side and an 906 00:51:30,710 --> 00:51:27,539 angle on the other one okay 907 00:51:35,529 --> 00:51:30,720 such that inside inside the snow line 908 00:51:37,819 --> 00:51:35,539 only compounds and molecules more 909 00:51:40,910 --> 00:51:37,829 resistant to heat them water could 910 00:51:44,359 --> 00:51:40,920 survive okay like silicates for example 911 00:51:45,829 --> 00:51:44,369 and and so only rocky bodies were formed 912 00:51:48,950 --> 00:51:45,839 with the material the solid material 913 00:51:53,599 --> 00:51:48,960 inside outside is tell is that rock and 914 00:51:57,260 --> 00:51:53,609 ice would have allowed for larger faster 915 00:52:01,120 --> 00:51:57,270 buildup of planetary cores and then a 916 00:52:03,890 --> 00:52:01,130 faster accretion of gas to be the big 917 00:52:10,010 --> 00:52:03,900 gas atmospheres of the gas giants 918 00:52:13,940 --> 00:52:10,020 okay now this simplified story that I 919 00:52:17,240 --> 00:52:13,950 just told still still very much assumed 920 00:52:19,480 --> 00:52:17,250 nowadays okay and it has important 921 00:52:23,480 --> 00:52:19,490 implications on what we can learn about 922 00:52:26,870 --> 00:52:23,490 exoplanet composition by looking at from 923 00:52:29,329 --> 00:52:26,880 looking at protoplanetary discs so let's 924 00:52:30,980 --> 00:52:29,339 look at the section of a protein from 925 00:52:37,849 --> 00:52:30,990 the vendor disc okay let's take it and 926 00:52:39,859 --> 00:52:37,859 let's take a section star and here and 927 00:52:42,650 --> 00:52:39,869 let's summarize in a cartoon the 928 00:52:45,470 --> 00:52:42,660 ingredients the factors that the process 929 00:52:47,690 --> 00:52:45,480 that we have taught so far okay so we 930 00:52:50,660 --> 00:52:47,700 have the dust grains small dust grains 931 00:52:52,819 --> 00:52:50,670 that grow in sizes okay at some point 932 00:52:53,690 --> 00:52:52,829 that they grow enough to fill a gas 933 00:52:55,910 --> 00:52:53,700 track and they 934 00:52:58,640 --> 00:52:55,920 feel they feel aghast ragged they 935 00:53:01,760 --> 00:52:58,650 migrate inward toward was the toward the 936 00:53:04,190 --> 00:53:01,770 star at some point for because of some 937 00:53:05,780 --> 00:53:04,200 processes they are kept they are stopped 938 00:53:10,400 --> 00:53:05,790 in their migration some of them are 939 00:53:13,010 --> 00:53:10,410 stopped and and they in this for example 940 00:53:15,140 --> 00:53:13,020 in these dust traps okay so that they 941 00:53:18,020 --> 00:53:15,150 can stay there long enough to build 942 00:53:19,760 --> 00:53:18,030 beginning mass and reached the 943 00:53:22,310 --> 00:53:19,770 planetesimals side the kilometer size 944 00:53:24,800 --> 00:53:22,320 and then start Procrit also also gaseous 945 00:53:26,450 --> 00:53:24,810 atmospheres okay those ways that make it 946 00:53:29,120 --> 00:53:26,460 to be inside the what is known I mean 947 00:53:30,890 --> 00:53:29,130 here has this strange because of the 948 00:53:32,960 --> 00:53:30,900 thermal temperature and density 949 00:53:35,090 --> 00:53:32,970 structure of the disk which is more 950 00:53:37,760 --> 00:53:35,100 complicated than a simple mind okay 951 00:53:48,950 --> 00:53:37,770 inside we have we have a separation so 952 00:53:52,550 --> 00:53:48,960 on will agree on for example of so while 953 00:53:54,530 --> 00:53:52,560 the processes that happen in the planet 954 00:53:56,870 --> 00:53:54,540 formation region inside the disk are 955 00:54:02,150 --> 00:53:56,880 hidden to our eyes we cannot see them 956 00:54:04,730 --> 00:54:02,160 okay we can observe the molecular gas in 957 00:54:08,330 --> 00:54:04,740 the inner disk through the infrared 958 00:54:14,000 --> 00:54:08,340 radiation of the gas okay and it is very 959 00:54:18,080 --> 00:54:14,010 recent in the last years that warm water 960 00:54:20,090 --> 00:54:18,090 and emission from molecules with carbon 961 00:54:22,490 --> 00:54:20,100 inside has been discovered in 962 00:54:24,770 --> 00:54:22,500 protoplanetary disk and another this is 963 00:54:26,600 --> 00:54:24,780 another achieved an achievement of 964 00:54:29,060 --> 00:54:26,610 another NASA Telescope the Spitzer Space 965 00:54:30,410 --> 00:54:29,070 Telescope okay and here you see here we 966 00:54:34,190 --> 00:54:30,420 use the trois copy inference 967 00:54:36,170 --> 00:54:34,200 spectroscopy to identify the molecules 968 00:54:39,170 --> 00:54:36,180 in the gas that produced the emission 969 00:54:41,240 --> 00:54:39,180 okay we have here the observations and 970 00:54:43,310 --> 00:54:41,250 here a model where you basically see 971 00:54:45,380 --> 00:54:43,320 that all the Wiggles you see well the 972 00:54:49,490 --> 00:54:45,390 majority of the Wiggles are due to water 973 00:54:53,630 --> 00:54:49,500 vapour and this colored ones are due to 974 00:54:56,870 --> 00:54:53,640 molecules that contain carbon okay so 975 00:54:59,510 --> 00:54:56,880 this tells us that now we are able to 976 00:55:00,980 --> 00:54:59,520 trace some molecules and not some 977 00:55:04,600 --> 00:55:00,990 irrelevant ones we are talking about 978 00:55:08,230 --> 00:55:04,610 water and carbon carbon B molecules okay 979 00:55:10,420 --> 00:55:08,240 back when they were in the disk okay and 980 00:55:13,690 --> 00:55:10,430 we can try to come to make a spirit to 981 00:55:17,190 --> 00:55:13,700 connect them to the composition of the 982 00:55:19,780 --> 00:55:17,200 exoplanets okay let's see what we can do 983 00:55:21,970 --> 00:55:19,790 one one example what what we can do with 984 00:55:24,910 --> 00:55:21,980 these kind of observations for example 985 00:55:28,360 --> 00:55:24,920 let's take the composition of one of our 986 00:55:34,210 --> 00:55:28,370 earth and the Sun okay and let's compare 987 00:55:39,190 --> 00:55:34,220 them so the the black line here is where 988 00:55:41,050 --> 00:55:39,200 all elements that we consider would lie 989 00:55:42,670 --> 00:55:41,060 they would lie on this land is the 990 00:55:45,220 --> 00:55:42,680 composition of Earth and the Sun is 991 00:55:50,350 --> 00:55:45,230 exactly the same okay and we see that 992 00:55:54,550 --> 00:55:50,360 this is this is true for many elements 993 00:55:55,980 --> 00:55:54,560 lie at least close to this line okay but 994 00:55:59,200 --> 00:55:55,990 some do not 995 00:56:02,560 --> 00:55:59,210 for example let me draw your attention 996 00:56:05,200 --> 00:56:02,570 to carbon that is under a bundle toward 997 00:56:07,330 --> 00:56:05,210 okay if it is lower than the line it 998 00:56:11,530 --> 00:56:07,340 means that this under abundant north by 999 00:56:14,800 --> 00:56:11,540 it by at most by almost a factor 10,000 1000 00:56:16,960 --> 00:56:14,810 okay if you think how much carbon is is 1001 00:56:19,600 --> 00:56:16,970 essential for for life on Earth you may 1002 00:56:22,860 --> 00:56:19,610 be you may be surprised by by by seeing 1003 00:56:31,090 --> 00:56:22,870 how little carbon there is on earth okay 1004 00:56:33,850 --> 00:56:31,100 now this may find an explanation in the 1005 00:56:37,750 --> 00:56:33,860 observations of protoplanetary discs and 1006 00:56:40,810 --> 00:56:37,760 in particular in the in the imprint that 1007 00:56:43,150 --> 00:56:40,820 is given by no lines in protoplanetary 1008 00:56:46,630 --> 00:56:43,160 discs to the composition of exoplanets 1009 00:56:50,350 --> 00:56:46,640 let's look at this plot from people in 1010 00:56:54,040 --> 00:56:50,360 2011 so far I've talked only about only 1011 00:56:56,200 --> 00:56:54,050 of one snow line the water snow line but 1012 00:56:58,630 --> 00:56:56,210 actually in in protoplanetary discs 1013 00:57:01,540 --> 00:56:58,640 every molecule has its own stone on 1014 00:57:04,600 --> 00:57:01,550 which is the location in the disk okay 1015 00:57:05,180 --> 00:57:04,610 the star is here we go further round the 1016 00:57:07,599 --> 00:57:05,190 temperature 1017 00:57:14,510 --> 00:57:07,609 Croesus in this direction the star okay 1018 00:57:17,210 --> 00:57:14,520 so all every molecule has its own snow 1019 00:57:20,480 --> 00:57:17,220 line where on one side further from the 1020 00:57:23,680 --> 00:57:20,490 star it's a nice only nice for him in 1021 00:57:27,349 --> 00:57:23,690 the ice form and closely easing the gas 1022 00:57:28,790 --> 00:57:27,359 okay so you have it for example waters 1023 00:57:32,480 --> 00:57:28,800 you to a co okay 1024 00:57:34,910 --> 00:57:32,490 co freezes at much lower temperatures 1025 00:57:38,079 --> 00:57:34,920 than water so there's no line of CO is 1026 00:57:43,280 --> 00:57:38,089 much further out okay in the disk and 1027 00:57:46,220 --> 00:57:43,290 co2 in between water as you so in this 1028 00:57:47,900 --> 00:57:46,230 plot here that is really a very 1029 00:57:51,410 --> 00:57:47,910 interesting result from the last years 1030 00:57:55,099 --> 00:57:51,420 and even this one will grow in interest 1031 00:58:00,069 --> 00:57:55,109 and in related papers in the next years 1032 00:58:04,370 --> 00:58:00,079 for sure we see that the composition the 1033 00:58:08,329 --> 00:58:04,380 composition of the gas this line and the 1034 00:58:11,210 --> 00:58:08,339 solids the solid grains in the disk this 1035 00:58:14,960 --> 00:58:11,220 this one line the composition in terms 1036 00:58:17,930 --> 00:58:14,970 of karbala balances as compared to 1037 00:58:20,599 --> 00:58:17,940 oxygen amount the number of carbon atoms 1038 00:58:23,180 --> 00:58:20,609 compared to oxygen atoms okay the 1039 00:58:28,099 --> 00:58:23,190 composition changes every time that 1040 00:58:30,170 --> 00:58:28,109 there is no line okay because a in any 1041 00:58:32,210 --> 00:58:30,180 given location of the disk we have 1042 00:58:34,339 --> 00:58:32,220 different contributions to the gas to 1043 00:58:35,930 --> 00:58:34,349 the solids depending on which molecules 1044 00:58:37,990 --> 00:58:35,940 are in the gas phase only the solid 1045 00:58:41,650 --> 00:58:38,000 phase okay 1046 00:58:45,170 --> 00:58:41,660 such that we can imagine that if 1047 00:58:47,839 --> 00:58:45,180 depending on where in exoplanet 1048 00:58:50,510 --> 00:58:47,849 forms in the linker it will have a 1049 00:58:52,250 --> 00:58:50,520 different composition okay depending on 1050 00:58:55,550 --> 00:58:52,260 the location where it forms in the disk 1051 00:58:57,680 --> 00:58:55,560 and not only the planet but also plan 1052 00:59:01,190 --> 00:58:57,690 the planet atmosphere as compared to the 1053 00:59:09,650 --> 00:59:01,200 planet surface in particular we will 1054 00:59:12,859 --> 00:59:09,660 have carbon rich atmospheres for for for 1055 00:59:15,829 --> 00:59:12,869 a large extent in radii while we will 1056 00:59:17,270 --> 00:59:15,839 have carbon poor surfaces for foreign 1057 00:59:22,260 --> 00:59:17,280 foreign 1058 00:59:25,200 --> 00:59:22,270 okay and this could explain a recent 1059 00:59:27,510 --> 00:59:25,210 exotic example the pizza panel was well 1060 00:59:30,299 --> 00:59:27,520 being who was proposed to have looking 1061 00:59:34,710 --> 00:59:30,309 at its atmosphere it's not Jupiter this 1062 00:59:36,450 --> 00:59:34,720 one looking at it at my atmosphere it 1063 00:59:39,000 --> 00:59:36,460 was proposed that the seat wall ratio 1064 00:59:42,210 --> 00:59:39,010 the composition in terms of siendo was 1065 00:59:44,819 --> 00:59:42,220 close to one must be close to one okay 1066 00:59:47,010 --> 00:59:44,829 this was what was proposed and this is 1067 00:59:48,450 --> 00:59:47,020 very exotic very strange compared to 1068 00:59:50,789 --> 00:59:48,460 what we find in the in the solar system 1069 00:59:54,210 --> 00:59:50,799 this is the seat wall the composition of 1070 00:59:56,670 --> 00:59:54,220 the Sun okay in terms of siendo and and 1071 00:59:59,309 --> 00:59:56,680 the the an exoplanet like this could be 1072 01:00:02,039 --> 00:59:59,319 explained if it formed in a location in 1073 01:00:05,609 --> 01:00:02,049 a comparable location in its own 1074 01:00:12,029 --> 01:00:05,619 protoplanetary disk okay this could also 1075 01:00:14,400 --> 01:00:12,039 explain maybe why is carbon poor okay if 1076 01:00:17,329 --> 01:00:14,410 it formed in a location of the proto 1077 01:00:20,039 --> 01:00:17,339 plant our protoplanetary disk where 1078 01:00:23,750 --> 01:00:20,049 carbon was primarily in the gas phase 1079 01:00:27,089 --> 01:00:23,760 not in the solid phase for example in co 1080 01:00:33,630 --> 01:00:27,099 so this is where we are going now in 1081 01:00:35,430 --> 01:00:33,640 this field we are working on finding a 1082 01:00:38,220 --> 01:00:35,440 link between the composition of 1083 01:00:40,500 --> 01:00:38,230 protoplanetary disks and the composition 1084 01:00:42,510 --> 01:00:40,510 of planets exoplanets and plants that 1085 01:00:45,569 --> 01:00:42,520 phone is a protoplanetary disc in an 1086 01:00:46,950 --> 01:00:45,579 attempt to build a story to build to 1087 01:00:50,490 --> 01:00:46,960 build a scenario where ever we 1088 01:00:52,680 --> 01:00:50,500 understand why and how certain kinds of 1089 01:00:55,349 --> 01:00:52,690 planets can form in certain discs and 1090 01:01:00,380 --> 01:00:55,359 why not others for example it's very 1091 01:01:05,490 --> 01:01:00,390 early in this okay 1092 01:01:12,080 --> 01:01:05,500 and now we are at the end so we made it 1093 01:01:19,970 --> 01:01:14,660 a rocket ball let's say even with 1094 01:01:21,770 --> 01:01:19,980 another sphere okay second step we 1095 01:01:23,630 --> 01:01:21,780 addressed also the composition so we 1096 01:01:25,670 --> 01:01:23,640 don't have only a rocket ball but we 1097 01:01:29,150 --> 01:01:25,680 have something that we can call a planet 1098 01:01:31,790 --> 01:01:29,160 okay and we saw how the composition of 1099 01:01:33,380 --> 01:01:31,800 the natural disk may imprint the 1100 01:01:37,700 --> 01:01:33,390 composition of the exoplanet of the 1101 01:01:41,450 --> 01:01:37,710 planet but the talk tonight the title 1102 01:01:46,730 --> 01:01:41,460 says new worlds not simply planets okay 1103 01:01:49,730 --> 01:01:46,740 and the end world suggests something 1104 01:01:53,690 --> 01:01:49,740 more than simply a rocky ball with some 1105 01:01:57,880 --> 01:01:53,700 composition floating into space world 1106 01:02:01,490 --> 01:01:57,890 suggests complexity diversity and life 1107 01:02:04,550 --> 01:02:01,500 so at the end of this talk I have to at 1108 01:02:06,230 --> 01:02:04,560 least mention an interesting symposium 1109 01:02:09,070 --> 01:02:06,240 that we had just a couple of months ago 1110 01:02:12,380 --> 01:02:09,080 here a space telescope in this room 1111 01:02:15,530 --> 01:02:12,390 called habitable worlds across time and 1112 01:02:18,020 --> 01:02:15,540 space we talked for days and we 1113 01:02:20,930 --> 01:02:18,030 discussed for days about the details and 1114 01:02:24,680 --> 01:02:20,940 many facets of the of this exciting 1115 01:02:28,820 --> 01:02:24,690 topic and that day I was I was surprised 1116 01:02:32,060 --> 01:02:28,830 that the final discussion we found 1117 01:02:34,670 --> 01:02:32,070 ourselves still addressing some 1118 01:02:38,060 --> 01:02:34,680 fundamental questions what is 1119 01:02:40,130 --> 01:02:38,070 habitability how can we define it for it 1120 01:02:44,000 --> 01:02:40,140 so planets and how can we search for 1121 01:02:48,380 --> 01:02:44,010 life beyond Earth and the all these 1122 01:02:50,600 --> 01:02:48,390 questions are still very often so if the 1123 01:02:54,290 --> 01:02:50,610 mystery addressed tonight was not enough 1124 01:02:57,170 --> 01:02:54,300 intriguing so far the problem of 1125 01:03:00,770 --> 01:02:57,180 habitability makes it the challenge that 1126 01:03:02,390 --> 01:03:00,780 we that is and will drive research for 1127 01:03:05,360 --> 01:03:02,400 for many years to come and also the 1128 01:03:08,260 --> 01:03:05,370 interest of the public for sure and no 1129 01:03:12,230 --> 01:03:08,270 doubt that we will be surprised 1130 01:03:15,260 --> 01:03:12,240 respectively scholars but desperately in 1131 01:03:17,390 --> 01:03:15,270 the article challenges and the 1132 01:03:20,600 --> 01:03:17,400 unexpected are the two pillars of 1133 01:03:23,750 --> 01:03:20,610 cutting-edge research and triggers for 1134 01:03:23,760 --> 01:03:47,480 thank you 1135 01:03:57,290 --> 01:03:49,820 anyway we've got time for some questions 1136 01:04:04,970 --> 01:03:57,300 please raise your hands if you want to 1137 01:04:10,370 --> 01:04:04,980 repeat experiment please okay let me try 1138 01:04:11,120 --> 01:04:10,380 one of the gas giant Saturn how does it 1139 01:04:13,190 --> 01:04:11,130 get stirred 1140 01:04:15,710 --> 01:04:13,200 what's down inside this drawls the gas 1141 01:04:20,390 --> 01:04:15,720 it they probably have trouble keeping 1142 01:04:23,060 --> 01:04:20,400 gas on Mars because it's too light so 1143 01:04:26,090 --> 01:04:23,070 you're asking what's inside and settle 1144 01:04:33,580 --> 01:04:26,100 just a loser get started and what's 1145 01:04:36,620 --> 01:04:33,590 there so the idea is that you made or 1146 01:04:42,170 --> 01:04:36,630 rocky terrestrial planets in the inner 1147 01:04:45,020 --> 01:04:42,180 disk closer to the star and apply rocky 1148 01:04:47,660 --> 01:04:45,030 cores for the four giant planets if they 1149 01:04:50,450 --> 01:04:47,670 have rocky cores III don't think it's 1150 01:04:52,850 --> 01:04:50,460 still super clear for our own giant 1151 01:04:55,790 --> 01:04:52,860 plants so it's not clear in general but 1152 01:04:58,610 --> 01:04:55,800 the idea is that even even gas giants 1153 01:05:14,390 --> 01:04:58,620 have a rocky calling in in them that 1154 01:05:17,510 --> 01:05:14,400 maybe the size of the of the rocky rocky 1155 01:05:21,050 --> 01:05:17,520 fast enough to to form when there is 1156 01:05:23,540 --> 01:05:21,060 still a lot of gas around then as I said 1157 01:05:27,020 --> 01:05:23,550 at some point the gravity kicks in a lot 1158 01:05:29,150 --> 01:05:27,030 and so you create a lot of gas from from 1159 01:05:31,490 --> 01:05:29,160 the surrounding from from the wing of 1160 01:05:34,280 --> 01:05:31,500 material okay at that location 1161 01:05:36,770 --> 01:05:34,290 okay and so it's a problem also of 1162 01:05:39,590 --> 01:05:36,780 timescales how fast you can build up 1163 01:05:41,960 --> 01:05:39,600 this course okay so in in the reaches 1164 01:05:46,510 --> 01:05:41,970 outside this simplified view of there's 1165 01:05:50,570 --> 01:05:46,520 no line being their eyes other than rock 1166 01:05:53,960 --> 01:05:50,580 solid material rock and ice 1167 01:05:56,720 --> 01:05:53,970 it's it's also seen by from experiments 1168 01:05:58,730 --> 01:05:56,730 that dyes helps a lot in building up 1169 01:06:01,640 --> 01:05:58,740 material because it's more sticky there 1170 01:06:04,100 --> 01:06:01,650 are a lot of experiments done with this 1171 01:06:06,290 --> 01:06:04,110 little quiz and try to see how they 1172 01:06:08,780 --> 01:06:06,300 stick and if they stick or not depending 1173 01:06:11,390 --> 01:06:08,790 on the velocity and but it seems that 1174 01:06:13,370 --> 01:06:11,400 the ice helps a lot okay so if if 1175 01:06:16,760 --> 01:06:13,380 outside of is known and you can build up 1176 01:06:21,110 --> 01:06:16,770 quickly a rocky core made of rock and 1177 01:06:25,430 --> 01:06:21,120 and dies then there is a runaway process 1178 01:06:56,270 --> 01:06:25,440 that accretes gas and this is a way to 1179 01:06:59,600 --> 01:06:56,280 explain everything you can think of is 1180 01:07:01,700 --> 01:06:59,610 there so I cannot tell you a specific 1181 01:07:12,670 --> 01:07:01,710 example we can look it up afterwards 1182 01:07:22,970 --> 01:07:17,510 created by NASA so the dead I'm sure we 1183 01:07:26,180 --> 01:07:22,980 can find one we have now so we can find 1184 01:07:31,640 --> 01:07:26,190 one there is really a big large variety 1185 01:07:34,310 --> 01:07:31,650 of compositions and size unless the 1186 01:07:39,110 --> 01:07:34,320 universe is not stranger than we 1187 01:07:47,640 --> 01:07:43,890 the the moons of Saturn and Jupiter are 1188 01:07:58,110 --> 01:07:47,650 they considered mainly rocky or are they 1189 01:08:02,390 --> 01:07:58,120 mostly they mix dynamics so some of very 1190 01:08:06,660 --> 01:08:02,400 much eyes some rocky with with yeah 1191 01:08:23,160 --> 01:08:06,670 actually interestingly in in the plot 1192 01:08:26,760 --> 01:08:23,170 that I showed here this one here the the 1193 01:08:29,040 --> 01:08:26,770 green points and III it's hidden okay 1194 01:08:31,770 --> 01:08:29,050 because I wanted to make it simpler but 1195 01:08:34,620 --> 01:08:31,780 the green points are the satellites of 1196 01:08:36,900 --> 01:08:34,630 gas giants so there is an interesting 1197 01:08:41,850 --> 01:08:36,910 overlap between the super Earths 1198 01:08:50,840 --> 01:08:41,860 population and the gas giant satellite 1199 01:08:54,060 --> 01:08:50,850 population there is this interesting 1200 01:09:07,620 --> 01:08:54,070 similarity that may suggest of a similar 1201 01:09:15,490 --> 01:09:10,689 it's a planetary system and these super 1202 01:09:19,390 --> 01:09:15,500 rods and then here the mass is scared 1203 01:09:21,789 --> 01:09:19,400 with the rate with the mass of the star 1204 01:09:23,709 --> 01:09:21,799 and for the giant line satellites is 1205 01:09:26,499 --> 01:09:23,719 scaled with the mass of the giant gas 1206 01:09:29,789 --> 01:09:26,509 giant okay so there is some story behind 1207 01:09:32,220 --> 01:09:29,799 that but but there is this seminar 1208 01:09:41,559 --> 01:09:32,230 hinting at the possibility in our 1209 01:09:43,149 --> 01:09:41,569 process there are first time yes yes so 1210 01:09:47,559 --> 01:09:43,159 you might have mentioned this but like 1211 01:09:49,839 --> 01:09:47,569 you said when they for like was it 1 1212 01:09:54,189 --> 01:09:49,849 meter bigots some of them get like 1213 01:09:57,729 --> 01:09:54,199 sucked into the start yeah what-what 1214 01:10:06,609 --> 01:09:57,739 exactly softly all all the planets that 1215 01:10:10,359 --> 01:10:06,619 were formed so what exactly we don't 1216 01:10:11,649 --> 01:10:10,369 know okay but we have to again we have 1217 01:10:13,720 --> 01:10:11,659 the theoretical approach and the 1218 01:10:20,250 --> 01:10:13,730 observation approach observationally 1219 01:10:26,200 --> 01:10:24,209 millimeter sized grains that are not 1220 01:10:28,839 --> 01:10:26,210 homogeneously distributed in the disk 1221 01:10:31,209 --> 01:10:28,849 but clamped in one region okay so that 1222 01:10:34,209 --> 01:10:31,219 that thing that observation is telling 1223 01:10:36,879 --> 01:10:34,219 us that there is some process that is it 1224 01:10:38,589 --> 01:10:36,889 that is keeping them there okay even if 1225 01:10:40,870 --> 01:10:38,599 we don't know what it is okay 1226 01:10:42,370 --> 01:10:40,880 on the theoretical side that there there 1227 01:10:44,680 --> 01:10:42,380 have been a lot of creativity and 1228 01:10:47,320 --> 01:10:44,690 imagination to try to explain that okay 1229 01:10:50,589 --> 01:10:47,330 and so that the idea is that that there 1230 01:10:53,950 --> 01:10:50,599 that there are these regions of over 1231 01:10:55,810 --> 01:10:53,960 density over densities in in that is 1232 01:11:00,459 --> 01:10:55,820 such that the density is not the same 1233 01:11:03,640 --> 01:11:00,469 okay so these these these grains while 1234 01:11:06,189 --> 01:11:03,650 they for example one is this I said one 1235 01:11:08,840 --> 01:11:06,199 is the snowline okay there's no name is 1236 01:11:10,760 --> 01:11:08,850 the region where you have 1237 01:11:13,190 --> 01:11:10,770 one side ice and the other side gas okay 1238 01:11:15,110 --> 01:11:13,200 if you have a sharp region where on the 1239 01:11:17,480 --> 01:11:15,120 on one side you have a lot of gas on the 1240 01:11:20,540 --> 01:11:17,490 other side you you don't you have the 1241 01:11:22,490 --> 01:11:20,550 same matter the same monocle for the 1242 01:11:27,230 --> 01:11:22,500 river water but in solid there is a 1243 01:11:29,090 --> 01:11:27,240 discontinuity so in in density of gas 1244 01:11:30,800 --> 01:11:29,100 material okay because on one side you 1245 01:11:34,040 --> 01:11:30,810 have a lot on the absolute you have less 1246 01:11:38,360 --> 01:11:34,050 okay that would be a a density region 1247 01:11:41,600 --> 01:11:38,370 where when the swings could be stopped 1248 01:11:43,790 --> 01:11:41,610 okay even though some still make it 1249 01:11:45,800 --> 01:11:43,800 through and produce the gas that is seen 1250 01:11:47,540 --> 01:11:45,810 in the inner disk of the in the in 1251 01:11:49,400 --> 01:11:47,550 England disk because they evaporate ice 1252 01:11:51,770 --> 01:11:49,410 is evaporate there and then there is 1253 01:11:55,850 --> 01:11:51,780 this proposed that there is a pre 1254 01:11:57,470 --> 01:11:55,860 diffusion of gas outside beyond the 1255 01:11:59,900 --> 01:11:57,480 stone and again building up again 1256 01:12:04,010 --> 01:11:59,910 freezing out water for example and 1257 01:12:07,730 --> 01:12:04,020 building up again material the solid 1258 01:12:09,170 --> 01:12:07,740 bodies beyond this one okay we don't 1259 01:12:11,110 --> 01:12:09,180 have a clear idea that there are many 1260 01:12:14,150 --> 01:12:11,120 complicated models to try to explain how 1261 01:12:16,910 --> 01:12:14,160 you can stop this grains there okay but 1262 01:12:52,569 --> 01:12:16,920 we have evidence that that happens okay 1263 01:13:09,169 --> 01:13:07,069 the answer to his question ishow two 1264 01:13:13,459 --> 01:13:09,179 unexpected things but Denis explain them 1265 01:13:19,279 --> 01:13:13,469 okay and actually one is still very 1266 01:13:21,169 --> 01:13:19,289 mysterious the idea is that and a lot of 1267 01:13:24,260 --> 01:13:21,179 development has been done even at that 1268 01:13:31,279 --> 01:13:24,270 time when these two Swiss guys were able 1269 01:13:33,410 --> 01:13:31,289 to from the theoretical side they had to 1270 01:13:36,649 --> 01:13:33,420 come up with something okay because they 1271 01:13:39,859 --> 01:13:36,659 had to explain it in some way and the 1272 01:13:42,140 --> 01:13:39,869 idea was that the the planet forms outer 1273 01:13:44,839 --> 01:13:42,150 for further out in the disk but then 1274 01:13:47,359 --> 01:13:44,849 migrates in okay I talked about the 1275 01:13:50,229 --> 01:13:47,369 migration of the small solids but the 1276 01:13:54,680 --> 01:13:50,239 similar migration may happen for 1277 01:13:56,419 --> 01:13:54,690 protoplanets or all planets okay by 1278 01:13:58,430 --> 01:13:56,429 interaction with the gas again so the 1279 01:14:00,439 --> 01:13:58,440 idea to explain there to explain the 1280 01:14:04,040 --> 01:14:00,449 population of hot Jupiter is that they 1281 01:14:04,689 --> 01:14:04,050 migrate towards the star after they are 1282 01:14:12,200 --> 01:14:04,699 formed 1283 01:14:16,209 --> 01:14:12,210 that's the sorry back there yes the 1284 01:14:20,479 --> 01:14:16,219 given radius from any Sun in this early 1285 01:14:22,160 --> 01:14:20,489 formation time are they all going at the 1286 01:14:25,100 --> 01:14:22,170 same rate of speed or do they go at 1287 01:14:28,310 --> 01:14:25,110 different speed I'm sorry can you did 1288 01:14:32,390 --> 01:14:28,320 the particles going which might vary in 1289 01:14:34,549 --> 01:14:32,400 terms of size do they end composition do 1290 01:14:38,060 --> 01:14:34,559 they all go at the same speed at a given 1291 01:14:42,109 --> 01:14:38,070 radius from some star or do they go at 1292 01:14:46,790 --> 01:14:42,119 different speeds it's an interesting 1293 01:14:54,870 --> 01:14:51,149 they go at different speeds when it 1294 01:14:57,270 --> 01:14:54,880 frozen when the soil particles are still 1295 01:14:59,550 --> 01:14:57,280 in random in the gas so when the disk is 1296 01:15:04,290 --> 01:14:59,560 still in the early phases and you have 1297 01:15:06,300 --> 01:15:04,300 gas and dust together at that point when 1298 01:15:08,790 --> 01:15:06,310 the particles the solid particles are 1299 01:15:15,750 --> 01:15:08,800 small enough they simply follow the gas 1300 01:15:18,479 --> 01:15:15,760 okay the reason why there is this 1301 01:15:23,640 --> 01:15:18,489 meter-sized barrier problem one of the 1302 01:15:26,459 --> 01:15:23,650 reasons is that when the solid particles 1303 01:15:33,689 --> 01:15:26,469 stick together and grow enough in size 1304 01:15:36,600 --> 01:15:33,699 at some point when they grow enough in 1305 01:15:38,520 --> 01:15:36,610 solids they start to be to decouple from 1306 01:15:42,149 --> 01:15:38,530 the gas because they are too big to 1307 01:15:45,689 --> 01:15:42,159 follow entirely the gas when they start 1308 01:15:47,280 --> 01:15:45,699 to do that they start to interact with 1309 01:15:49,020 --> 01:15:47,290 the gas in a different way okay they 1310 01:15:51,660 --> 01:15:49,030 start to go at their own velocity em 1311 01:15:53,640 --> 01:15:51,670 feel the gas drag okay that's that this 1312 01:15:56,040 --> 01:15:53,650 is the reason of the gas drag that then 1313 01:15:58,950 --> 01:15:56,050 they feel sucked in really sucked in 1314 01:16:02,609 --> 01:15:58,960 through the disc okay onto the star so 1315 01:16:04,830 --> 01:16:02,619 it is indeed a man so different sizes of 1316 01:16:07,140 --> 01:16:04,840 the earth particles have do have 1317 01:16:09,959 --> 01:16:07,150 different different velocities because 1318 01:16:12,479 --> 01:16:09,969 they they interact in a different way 1319 01:16:17,270 --> 01:16:12,489 with the environment okay also the shape 1320 01:16:29,160 --> 01:16:17,280 matters to some extent the composition 1321 01:16:32,040 --> 01:16:29,170 not and I don't think the shape also so 1322 01:16:34,200 --> 01:16:32,050 in this kind of studies use that from 1323 01:16:36,979 --> 01:16:34,210 assuming the simplest conditions and you 1324 01:16:39,570 --> 01:16:36,989 assume dust grains that are spheres just 1325 01:16:44,070 --> 01:16:39,580 compact spheres with some composition 1326 01:16:46,229 --> 01:16:44,080 against a mass if they grow by speaking 1327 01:16:48,120 --> 01:16:46,239 of small particles is very happy they 1328 01:16:49,310 --> 01:16:48,130 are not spheres for they are fluffier 1329 01:16:52,330 --> 01:16:49,320 okay so 1330 01:16:54,860 --> 01:16:52,340 love experiments we see that when we 1331 01:16:57,440 --> 01:16:54,870 lower self when when we stick together 1332 01:17:00,080 --> 01:16:57,450 these dis particles they are not never 1333 01:17:03,470 --> 01:17:00,090 his fear but they are fluffier and then 1334 01:17:06,520 --> 01:17:03,480 again that would affect their lost yes 1335 01:17:17,960 --> 01:17:06,530 people could not an account for a 1336 01:17:24,080 --> 01:17:20,910 maybe in some in something III would 1337 01:17:27,530 --> 01:17:24,090 have to think in more details about that 1338 01:17:31,710 --> 01:17:27,540 sounds like a rolling back up on the 1339 01:17:35,100 --> 01:17:31,720 classic classically you would expect 1340 01:17:37,170 --> 01:17:35,110 that when you reach a certain size maybe 1341 01:17:38,700 --> 01:17:37,180 even assuming the simplified sphere okay 1342 01:17:40,350 --> 01:17:38,710 but when you reach a certain size you 1343 01:17:44,820 --> 01:17:40,360 start to the capital from the gas and 1344 01:17:48,270 --> 01:17:44,830 keep this gas track if the shady the 1345 01:17:49,979 --> 01:17:48,280 shape fluffier or less fluffy can matter 1346 01:17:54,960 --> 01:17:49,989 on this death-trap 1347 01:17:57,720 --> 01:17:54,970 III don't know in this detail I'd like 1348 01:18:00,330 --> 01:17:57,730 to thank doctor been solid for his time 1349 01:18:01,770 --> 01:18:00,340 tonight very excellent questions your 1350 01:18:04,350 --> 01:18:01,780 really deep thank you sir 1351 01:18:06,780 --> 01:18:04,360 I forgot to mention at the beginning 1352 01:18:11,130 --> 01:18:06,790 there is no observatory tonight we have